Information-provision control method, information reproduction system, information-provision apparatus, information reproduction apparatus and information-presentation control program

ABSTRACT

When the information-provision apparatus is providing an audio signal to the specific information reproduction apparatus, the user enters an operation input to the specific information reproduction apparatus to switch processing to reproduce an audio content from the specific information reproduction apparatus to another information reproduction apparatus. In this case, the specific information reproduction apparatus requests the information-provision apparatus to start an operation of providing the audio content to the other information reproduction apparatus specified in the operation input as an apparatus to newly reproduce the audio content. Then, the specific information reproduction apparatus requests the information-provision apparatus to end an operation of providing the audio content to the specific information reproduction apparatus specified in the operation input as an apparatus to terminate an operation of reproducing the audio content.

RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/101,027, entitled “Information-Provision Control Method, InformationReproduction System, Information-Provision Apparatus, InformationReproduction Apparatus And Information-Presentation Control Program,”filed Dec. 9, 2013, which is a continuation of U.S. patent applicationSer. No. 11/068,068, entitled “Information-Provision Control Method,Information Reproduction System, Information-Provision Apparatus,Information Reproduction Apparatus And Information-Presentation ControlProgram,” filed Feb. 28, 2005, now U.S. Pat. No. 8,713,126, which claimspriority to Japanese Patent Application No. JP2004-060561, filed Mar. 4,2004. Each of the foregoing documents is incorporated herein byreference in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates to an information-provision control methodadopted in an information reproduction system including at least oneinformation-provision apparatus and a plurality of informationreproduction apparatuses used for sequentially reproducing informationprovided by the information-provision apparatus, as well as relates tothis information reproduction system, the information-provisionapparatus, the information reproduction apparatus and aninformation-provision control program.

In recent years, with popularization of personal computers and theincreasing number of applications of the Internet, by using a personalcomputer at a home or at a working place, a large number of accesses toa server connected to the Internet can be made to download a variety ofcontent data and a large number of emails can be exchanged in a widerange of applications. In addition, the operations to download audio andvideo data from a server as content data by way of the Internet havebeen becoming regular day-to-day operations. For example, a technologyhas been proposed for an Internet-based chat system as a technologyallowing audio data to be provided at the same time to a plurality ofpersons participating in a chat to be listened to by the participants inthe same way as text data. For details of this technology, refer toJapanese Patent Laid-open No. 2001-184292, which is referred to aspatent reference 1.

In this way, through the so-called WAN (Wide Area Network),communication technologies have been dramatically making progress toprovide the user with a convenient application environment as evidencedby, among others, the fact that necessary information can be acquired ina short period of time at places such as a home and a working placewhereas information can be exchanged smoothly as advancements of effortsto share information.

Moreover, in addition to the WAN system, a LAN (Local Area Network)system can be constructed as a network connecting personal computers andperipheral apparatus to each other in a limited space such as a home orrooms inside a building. The LAN system is widely used as a system forallowing users to share resources such as files and a printer.

In the conventional LAN system employing UARTs (Universal AsynchronousReceiver-Transceivers), however, a sufficiently high communication speedcannot be assured, raising a problem that, for example, it takes toolong time to exchange audio data that should be transmitted at arequired communication speed of about 1.4 MBps (megabytes per second).

In addition, with recent introduction of a USB (Universal Serial Bus), apersonal computer becomes capable of transmitting audio data by way of aUSB terminal. Nevertheless, the maximum length of its cable is fixed at5 m. Thus, for example, even a personal computer located in the sameroom is not capable of playing the role of an active speaker.

With progress made in recent years in Internet technologies, however,communication using a TCP/IP (Transmission Control Protocol/InternetProtocol), which has been becoming popular, not only allows audio datato be transferred in a sufficiently short period of time given itscommunication speed and communication reliability, but also allows thelength of a cable used in a LAN system built at a place like a home tobe extended to a maximum of 100 m. Thus, sounds of music can distributedto any locations in the facility. In addition, through a piece ofequipment such as a Network HUB, the number of apparatus connectable tothe network can be increased.

On the top of that, if only audio data is to be transferred through agiven communication band, a plurality of pieces of audio data can betransmitted once simultaneously. Thus, by providing a server having asufficient processing power, it is possible to prepare an environment inwhich clients installed in a plurality of rooms are capable of listeningto desired audio data being distributed at the same time from theserver.

Accordingly, a personal computer installed at a home and a variety of AV(Audio/Visual) apparatus provided in rooms of the home can be connectedto each other through a LAN. With such a LAN, it is possible to build anenvironment in which contents stored in the personal computer can beenjoyed at a variety of places such as the living room, study room andbedroom of the home. Examples of the contents are audio data, video dataand AV data, which includes audio and video data collectedsynchronously.

Much like a WAN system, a LAN system also adopts a general method ofutilization by which any client desiring information outputs a requestfor the information to a server used as an information provider and theserver transmits the desired information to the server in response tothe request. If the LAN system adopting such a method includes aplurality of clients, the clients are allowed to make accesses to theserver simultaneously to receive a desired content at the same time.

By the way, the so-called home network system, which is a LAN systemconstructed at a home, is built in a house. Given such a home networksystem, the user raises a demand for a capability of enjoying a desiredcontent in a room in which the user desires to enjoy the content. Inthis case, the user issues a request to typically a personal computerfunctioning as a server through an AV apparatus located in the room.

In addition, the user also raises a demand for a capability of allowingthe user not to only listen to a desired audio content in a specificroom through a particular AV apparatus, but also to continuously listento the same audio content in another room through another AV apparatuslocated at the other room following a movement of the user from thespecific room to the other room. On the top of that, in this case, it isdesirable to merely require the user to operate only once either theparticular AV apparatus in the specific room immediately before themovement or the other AV apparatus in the other room after the movement.

In the conventional home network system, however, as general operationsto be carried out by the user on a particular AV apparatus in a specificroom to make an access to the server to search the server for a desiredcontent and control an operation to reproduce the content, normally, theuser is capable of operating the particular AV apparatus presumably onlyfor the purpose of reproducing the desired content in this AV apparatus.Thus, when the user moves from the specific room to another room afteroperating the particular AV apparatus, the user must stop the operationcarried out by the particular AV apparatus to reproduce the contentbefore the user moves from the specific room to the other room and thenoperate another AV apparatus installed in the other room in order torestart the operation to reproduce the desired content. Thus, from theuser point of view, the operatability of the conventional home networksystem is poor and the operation to reproduce a content is interruptedevery time the user moves from one room to another. That is to say, itis difficult to reproduce a content continuously.

SUMMARY OF THE INVENTION

It is thus an object of the present invention, which addresses theproblems described above, to provide an information-provision controlmethod capable of switching an operation to reproduce a content from onereproduction apparatus to another one in a simple operation carried outby the user without interrupting the operation to reproduce the content.

In addition, it is another object of the present invention to provide aninformation reproduction system capable of switching an operation toreproduce a content from one reproduction apparatus to another one in asimple operation carried out by the user without interrupting theoperation to reproduce the content as well as provide aninformation-provision apparatus and information reproduction apparatusto be included in the information reproduction system.

On the top of that, it is a further object of the present invention toprovide an information-provision control program capable of switching anoperation to reproduce a content from one reproduction apparatus toanother one in a simple operation carried out by the user withoutinterrupting the operation to reproduce the content.

According to a first aspect of the present invention, there is providedan information control method adopted in an information reproductionsystem including at least one information-provision apparatus and aplurality of information reproduction apparatuses each used forreproducing information received from said information-provisionapparatus, said information control method including the steps of:

letting one of said information reproduction apparatus request saidinformation-provision apparatus to transmit predetermined content datato a specific one of said information reproduction apparatus bytransmitting pieces of information to said information-provisionapparatus as content identification information used for identifyingsaid predetermined content data and apparatus identification informationused for designating said specific information reproduction apparatus asan information reproduction apparatus to receive said predeterminedcontent data transmitted by said information-provision apparatus;

letting said information-provision apparatus transmit said predeterminedcontent data to said specific information reproduction apparatus;

letting said specific information reproduction apparatus reproduce saidpredetermined content data;

requesting said information-provision apparatus to transmit saidpredetermined content data to a particular one of said informationreproduction apparatus by transmitting apparatus identificationinformation to said information-provision apparatus as information usedfor designating said particular information reproduction apparatus as aninformation reproduction apparatus to newly receive said predeterminedcontent data transmitted by said information-provision apparatus whereinsaid particular information reproduction apparatus is different fromsaid specific information reproduction apparatus;

letting said information-provision apparatus start transmitting saidpredetermined content data to said particular information reproductionapparatus; and

letting said particular information reproduction apparatus reproducesaid predetermined content data in a continuation operation to reproducesaid predetermined content data.

According to a second aspect of the present invention, there is providedan information reproduction system including at least oneinformation-provision apparatus and a plurality of informationreproduction apparatuses each used for reproducing information receivedfrom said information-provision apparatus wherein

said information-provision apparatus includes:

-   -   a presentation-request acceptance section for accepting a        request to start an operation of providing content data to any        specific one of said information reproduction apparatus;    -   an information-providing section for carrying out said operation        to provide content data to said specific information        reproduction apparatus in accordance with said request; and    -   a content-recipient modification section for changing any ones        of said information reproduction apparatus each designated as a        recipient of said content data, whereas    -   said information reproduction apparatus includes:        -   a reproduction section for reproducing content data; and        -   a recipient designation section for requesting said            information-provision apparatus to transmit predetermined            content data to any specific one of said information            reproduction apparatus by transmitting pieces of information            to said information-provision apparatus as content            identification information used for identifying said            predetermined content data and apparatus identification            information used for designating said specific information            reproduction apparatus as an information reproduction            apparatus to receive said predetermined content data as well            as requesting said information-provision apparatus to            transmit said predetermined content data to a particular one            of said information reproduction apparatus by transmitting            apparatus identification information to said            information-provision apparatus as information used for            designating said particular information reproduction            apparatus as an information reproduction apparatus to newly            receive said predetermined content data wherein said            particular information reproduction apparatus is different            from said specific information reproduction apparatus.

According to a third aspect of the present invention, there is providedan information-provision apparatus for providing content data to aplurality of information reproduction apparatuses each used forreproducing said content data received from said information-provisionapparatus, said information-provision apparatus including:

a presentation-request acceptance section for accepting a request tostart an operation to provide content data to any specific one of saidinformation reproduction apparatus;

an information-providing section for carrying out said operation toprovide content data to said specific information reproduction apparatusin accordance with said request; and

a content-recipient modification section for changing any ones of saidinformation reproduction apparatus each designated as a recipient ofsaid content data.

According to a fourth aspect of the present invention, there is providedan information reproduction apparatus for reproducing content datareceived from an information-provision apparatus, said informationreproduction apparatus including:

a reproduction section for reproducing content data; and

a recipient designation section for requesting saidinformation-provision apparatus to transmit predetermined content datato a specific information reproduction apparatus by transmitting piecesof information to said information-provision apparatus as contentidentification information used for identifying said predeterminedcontent data and apparatus identification information used fordesignating said specific information reproduction apparatus as aninformation reproduction apparatus to receive said predetermined contentdata as well as requesting said information-provision apparatus totransmit said predetermined content data to another informationreproduction apparatus by transmitting apparatus identificationinformation to said information-provision apparatus as information usedfor designating said other information reproduction apparatus as aninformation reproduction apparatus to newly receive said predeterminedcontent data.

According to a fifth aspect of the present invention, there is providedan information control program to be executed by a computer carrying outa process to control operations of reproducing information provided byat least an information-provision apparatus in a plurality ofinformation reproduction apparatuses each used for reproducing saidinformation, said information control program including the steps of:

letting one of said information reproduction apparatus request saidinformation-provision apparatus to transmit predetermined content datato a specific one of said information reproduction apparatus bytransmitting pieces of information to said information-provisionapparatus as content identification information used for identifyingsaid predetermined content data and apparatus identification informationused for designating said specific information reproduction apparatus asan information reproduction apparatus to receive said predeterminedcontent data transmitted by said information-provision apparatus;

letting said information-provision apparatus transmit said predeterminedcontent data to said specific information reproduction apparatus;

letting said specific information reproduction apparatus reproduce saidpredetermined content data;

requesting said information-provision apparatus to transmit saidpredetermined content data to a particular one of said informationreproduction apparatus by transmitting apparatus identificationinformation to said information-provision apparatus as information usedfor designating said particular information reproduction apparatus as aninformation reproduction apparatus to receive said predetermined contentdata transmitted by said information-provision apparatus wherein saidparticular information reproduction apparatus is different from saidspecific information reproduction apparatus;

letting said information-provision apparatus start transmitting saidpredetermined content data to said particular information reproductionapparatus; and

letting said particular information reproduction apparatus reproducesaid predetermined content data in a continuation operation to reproducesaid predetermined content data.

In accordance with the present invention, when any of theinformation-provision apparatus is providing the sameinformation-conveying signal to at least one of the informationreproduction apparatus at the same time, by providing one of theinformation reproduction apparatus with input specification informationdesignating at least one of the information reproduction apparatusemployed in the information reproduction system as new presentationtargets of the information-conveying signal and designating at least oneof the information reproduction apparatus as information-conveyingsignal recipients to be subjected to termination of an operation toprovide the information-conveying signal to the information-conveyingsignal recipients, the same information-conveying signal can betransmitted to the information reproduction apparatus each designated asthe new presentation target, and the information reproduction apparatusserving as the new presentation targets are each capable of reproducingthe information-conveying signal. In addition, the operation to providethe information-conveying signal to the information reproductionapparatus each designated as the information-conveying signal recipientto be subjected to termination of an operation to provide theinformation-conveying signal is terminated to end the operations carriedout by these information-conveying signal recipients to reproduce theinformation-conveying signal. Thus, with a simple operation carried bythe user, the same information-conveying signal can be switched from oneinformation reproduction apparatus to another without interrupting theoperation to reproduce the information-conveying signal.

In addition, if one of the information reproduction apparatus eachdesignated by the input specification information as the newpresentation target or one of the information reproduction apparatuseach designated by the input specification information as theinformation-conveying signal recipient to be subjected to termination ofan operation to provide the information-conveying signal is selected asthe information reproduction apparatus to receive the inputspecification information, when the user moves from a specific room toanother room, the user is capable of switching the sameinformation-conveying signal from one information reproduction apparatusinstalled in the specific room to another one installed in the otherroom by operating only one information reproduction apparatus actuallyreproducing the information-conveying signal in the specific or otherroom. Thus, convenience offered to the user is enhanced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a typical configuration of the home networksystem implemented by an embodiment of the present invention;

FIG. 2 is an explanatory diagram showing a protocol stack according tothe UPnP specifications;

FIG. 3 is a diagram showing a tree structure for managing contentsstored in a media server;

FIG. 4 is a block diagram showing the basic configuration of a server;

FIG. 5 is a block diagram showing the internal configuration of acommunication unit employed in a server;

FIG. 6 is a block diagram showing a typical configuration of an audioreproduction apparatus;

FIG. 7 is an explanatory diagram showing an outline of an operation,which is carried out in a whole home network system when an audioreproduction apparatus presently reproducing an audio content isoperated to switch an operation of reproducing the audio content toanother audio reproduction apparatus;

FIG. 8 shows a flowchart representing processing carried out by an audioreproduction apparatus functioning as a control point;

FIG. 9 shows a flowchart representing processing carried out by an audioreproduction apparatus functioning as a control point to switch anoperation of reproducing an audio content to another audio reproductionapparatus;

FIG. 10 shows a flowchart representing processing carried out by aserver functioning as a media server;

FIG. 11 shows a flowchart representing a processing procedure executedby an audio reproduction apparatus serving as a media renderer;

FIG. 12 is an explanatory diagram showing an outline of an operation,which is carried out in a whole home network system when an audioreproduction apparatus to be newly designated as an audio reproductionapparatus to reproduce an audio content is operated to switch anoperation of reproducing the audio content from another audioreproduction apparatus;

FIG. 13 is an explanatory diagram showing a typical process to switch anoperation of reproducing an audio content from one audio reproductionapparatus to a plurality of other audio reproduction apparatus;

FIGS. 14A and 14B are first diagrams showing typical select screens forselecting audio reproduction apparatus to serve as switching objects;

FIGS. 15A and 15B are second diagrams showing typical select screens forselecting audio reproduction apparatus to serve as switching objects;and

FIG. 16 shows a typical table used by an audio reproduction apparatusspecified as a switching object to end an operation of reproducing anaudio content as a table showing audio reproduction apparatus each to benewly designated as a switching object to start an operation ofreproducing the audio content.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are explained by referring todiagrams as follows. In the following description, it is assumed thatthe present invention is applied to a LAN system (or a home networksystem) built at a home.

[Configuration of the Home Network]

FIG. 1 is a diagram showing a typical configuration of the home networksystem implemented by an embodiment of the present invention.

The typical configuration of a home network system shown in FIG. 1includes servers 1 and 2, audio reproduction apparatus 3 to 5 as well asa LAN 6 for connecting the servers 1 and 2 as well as the audioreproduction apparatus 3 to 5 to each other.

Typically, the servers 1 and 2 are each an information-processingapparatus such as a personal computer. Each of the servers 1 and 2 has afunction for connection to the LAN 6 and a reproduction unit forreproducing data from a large-capacity storage medium such as an HDD(Hard Disk Drive) and from an optical disk such as a CD (Compact Disk)and a DVD (Digital Versatile Disk). The servers 1 and 2 are each capableof providing audio data recorded on the HDD, the CD or the DVD to theaudio reproduction apparatus 3 to 5 by way of the LAN 6. In thisembodiment, the servers 1 and 2 are installed in different rooms. Forexample, the servers 1 and 2 are installed in a living room and a studyroom respectively.

Examples of the audio reproduction apparatus 3 to 5 are a CD player anda radio tuner, which each have a function for connection to the LAN 6.Each of the audio reproduction apparatus 3 to 5 has the conventionalfunction for reading out audio data from a CD for reproduction orreceiving a radio broadcast signal for reproduction. In addition, theaudio reproduction apparatus 3 to 5 each have a function for receivingaudio data provided by the server 1 or 2 by way of the LAN 6, decodingthe received audio data and reproducing the decoded data. In thisembodiment, the audio reproduction apparatus 3 to 5 are installed indifferent rooms.

As described above, the servers 1 and 2 implemented by the embodimenteach have a function of an information-provision apparatus. On the otherhand, each of the audio reproduction apparatus 3 to 5 has a function ofa client (or an information reproduction apparatus) for receiving audiodata from the server 1 or 2 and reproducing the received data.

The user is capable of enjoying an audio content provided by the server1 or 2 to any one of the audio reproduction apparatus 3 to 5. That is tosay, each of the audio reproduction apparatus 3 to 5 is capable ofselecting the server 1 or 2 as a source of audio-data transmission independence on what audio data (or audio content) to be reproduced.

In addition, each of the audio reproduction apparatus 3 to 5 istypically implemented by the so-called network-participation electronicapparatus conforming to UPnP (Universal Plug & Play) specificationsannounced by Microsoft of the US in order to make connections betweenthe electronic apparatuses simple.

It is to be noted that the UPnP specifications can be applied to an IEEE(Institute of Electrical and Electronic Engineers) 802 network, which isa representative network in network communications each using a 10/100BASE-T Ethernet (a trademark). The UPnP specifications arespecifications for a group of protocols and a data format. The group ofprotocols includes an IP as well as a UDP (User Datagram Protocol) and aTCP of the IP. The UPnP specifications are provided to upgrade thefunctions of Internet standard communication (TCP/IP communication).

In addition, by adopting the UPnP specifications in the so-called CE(Consumer Electronics) apparatus such as an audio reproductionapparatus, the CE apparatus such as an audio reproduction apparatus,another CE apparatus and a personal computer are capable of mutuallyauthenticating each other with ease so that a service can be rendered byway of a network and executed in a simple as well as proper mannerwithout requiring the user to carry out cumbersome operations.

[Overview of the UPnP Specifications]

FIG. 2 is an explanatory diagram showing a protocol stack (or thestructure of a protocol group) according to the UPnP specifications.

As shown in FIG. 2, in accordance with the UPnP specifications, actualdata is transmitted and received by using Internet standardcommunication protocols. In addition, in order to implement originalfunctions of the UPnP specifications described below, a group ofprotocols such as an SSDP (Simple Service Discovery Protocol), a GENA(General Event Notification Architecture), a SOAP (Simple Object AccessProtocol) and an HTTP (HyperText Transfer Protocol) is used.

In addition, in accordance with the UPnP specifications, the structureof a protocol group also includes UPnP vendor definitions (UPnP VendorDefined), UPnP forum working committee definitions (UPnP Forum WorkingCommittee Defined) and UPnP device architecture definitions (UPnP DeviceArchitecture Defined) as shown in FIG. 2.

On the top of that, the UPnP specifications prescribe 6 functions, i.e.,addressing, discovery, description, control, eventing and presentation.

A UPnP apparatus such as an audio reproduction apparatus conforms toprescriptions referred to as an UPnP/AV/architecture in order to useaudio data by utilization of UPnP functions. A UPnP apparatus is definedas an electronic apparatus conforming to the UPnP specifications. UPnPapparatus in the UPnP/AV/architecture are classified into threecategories as follows.

In the UPnP/AV/architecture, UPnP apparatuses are classified into amedia server for providing contents, a control point functioning as acontrol terminal and a media renderer functioning as a reproductionapparatus. The media server corresponds to an apparatus generallyreferred to as a server in the network system. On the other hand, themedia renderer corresponds to an apparatus generally referred to as aclient in the network system.

The control point also referred to as a control apparatus is capable ofcontrolling UPnP apparatus connected to the network. Functions of thecontrol point allow the control point to be mounted on a media server ora media renderer, allow the control point to be mounted on allelectronic apparatus connected to the network and allow the controlpoint to be mounted on any ones of electronic apparatuses connected tothe network. In this embodiment, as an example, the servers 1 and 2 aswell as the audio reproduction apparatus 3 to 5 each have the functionsof the control point.

The addressing function prescribed in the UPnP specifications as afunction of a UPnP apparatus is a function to acquire an address foridentifying the UPnP apparatus itself in the IEEE802 network. In theaddressing function, a DHCP (Dynamic Host Configuration Protocol) or anAuto-IP is adopted.

The discovery function is carried out after the addressing. By carryingout the discovery, the control point is capable of discovering acontrolled target apparatus, which is either a media server or a mediarenderer. The control executed in this case is the SSDP described above.When any of electronic apparatus composing the network system isconnected to the IEEE802 network, the electronic apparatus broadcasts amessage for announcing a device address and service of its own to theIEEE802 network by transmitting a packet with a transmission destinationspecially unspecified. Receiving this broadcasted message, a controlpoint is capable of knowing what apparatus was just connected to theIEEE802 network.

An SSDP packet output by an electronic apparatus discovered by thecontrol point through execution of the discovery function as acontrolled device includes a URL (Uniform Resource Locator) of a devicedescription. By making an access to the URL, the control point iscapable of acquiring more detailed information on the device from thedevice description.

The information on the device includes icon information, a model name,the manufacturer, the commodity name (trade name) and a servicedescription explaining detailed information on a service rendered by thedevice. From these device description and the service description, thecontrol point is capable of knowing a method of making an access to thisdevice, which serves as a target apparatus. The device description andthe service description are expressed in an XML (eXtensible MarkupLanguage).

Control functions are classified into two large function categories,i.e., an action and a query. An action is carried out in accordance witha method prescribed in action information in the service description. Byinvoking an action, the control point is capable of operating the targetapparatus. A query is carried out to fetch device information referredto as a state variable from the service description. In these controlfunctions, a transport protocol called the SOAP mentioned earlier isutilized and expressed in the XML.

The eventing function is carried out by the target apparatus to informthe control point that information on the apparatus has been changed. Byanalyzing the service description of a target apparatus, the controlpoint is capable of identifying a variable indicating the targetapparatus from the information on the apparatus and receiving a noticeissued by the target apparatus when the variable is changed. In theeventing function, a transport protocol called the GENA mentionedearlier is utilized and expressed in the XML.

The presentation function is carried out to provide the user with acontrol section using a user interface. By making an access to apresentation URL described in the device description, it is possible toobtain a presentation page expressed in an XTML. With this function, apresentation can be made in the target apparatus.

By carrying out the UPnP functions described above, each UPnP apparatusis capable of not only participating in the network and entering a stateof being capable of carrying out communications without requiring theuser to specially carry out cumbersome operations, but alsoautomatically detecting another UPnP apparatus and establishing aconnection with the other UPnP apparatus.

Next, refer to FIG. 3, which is a diagram showing a tree structure formanaging contents stored in a media server.

The media server, which is a UPnP apparatus, includes an embeddedfunction (or service) called a CDS (Contents Directory Service). Bycarrying out this function, the media server is capable of informing acontrol point of how contents are stored in the media server. The CDSuses two kinds of objects of abstraction, i.e., a container and an item.The container and the item respectively correspond to the folder and thefile in Windows (a registered trademark), which is the name of an OS(Operating System) provided by Microsoft of the US. Containers and itemsalways form a tree structure like one shown in FIG. 3. It is to be notedthat, in this embodiment, a distributed audio content (or audio data) isan item in the tree structure shown in FIG. 3.

By acquiring the tree structure shown in FIG. 3 from a media server, acontrol point is capable of obtaining the URL of each of contentincluded in the tree structure. As explained earlier, the URL is a linkdescribing information on the location of a resource. Then, ifinformation on a desired audio content (or item) can be obtained, afunction of the media server can be used to carry out operations on theaudio data (or the audio track). The operations include an operation toreproduce the audio data and an operation to stop the reproduction ofthe audio data. The function used to carry out operations is referred toas an AV transport.

In this embodiment, as described earlier, the servers 1 and 2 as well asthe audio reproduction apparatus 3 to 5 are each put in a state of beingcapable of carrying out TCP/IP communications by execution of the UPnPaddressing function and authenticating each other by execution of theUPnP discovery function. Thus, each of the servers 1 and 2 as well asthe audio reproduction apparatus 3 to 5 is capable of grasping theconfiguration of the network and carrying out a communication with adesired electronic apparatus.

[Typical Configuration of the Server]

The following description explains a typical configuration of each ofthe electronic apparatus composing the home network system implementedby the embodiment. First of all, refer to FIG. 4, which is a blockdiagram showing the basic configuration of the server 1.

As shown in FIG. 4, the server 1 includes a communication terminal 11, acommunication unit 12, an HDD 13, a control unit 14, an input interface(I/F) 151, a key operation unit 152, a display interface (I/F) 153, adisplay unit 154, an external interface (I/F) 155 and a externalinput/output terminal 156. The communication terminal 11 is a terminalconnected to the LAN 6.

A cable of the LAN 6 is connected to the communication terminal 11. Thecommunication unit 12 is thus connected to the LAN 6 through thecommunication terminal 11 so that the server 1 is capable of exchangingdata with other apparatus. It is to be noted that the internalconfiguration of the communication unit 12 will be explained later indetail by referring to FIG. 5.

The HDD 13 is a storage device having a storage capacity large enoughfor storing data including a large number of digital contents orpresentation information. In addition, the HDD 13 is also used forstoring a variety of programs and data for processing. The HDD 13 alsoincludes a work area used in processes to decode a content and transmita content to another apparatus by way of the LAN 6.

The control unit 14 is a microcomputer for controlling other componentsin the server 1. The control unit 14 includes a CPU (Central ProcessingUnit) 141, a ROM (Read Only Memory) 142, a RAM (Random Access Memory)143 and an EEPROM (Electronically Erasable and Programmable ROM) 144,which are connected to each other by a CPU bus 145. It is to be notedthat the communication unit 12, the HDD 13, the input I/F 151, thedisplay I/F 153 and the external I/F 155 are also connected to the CPUbus 145 and controlled by the CPU 141 through the CPU bus 145.

The ROM 142 is a memory for storing programs to be executed by the CPU141 and data required in processing. The RAM 143 is a memory mainly usedas a work area in various kinds of processing. The EEPROM 144 is theso-called nonvolatile memory used for storing and holding data such as avariety of parameters.

The key operation unit 152 is an input unit for receiving operationinputs entered by the user. The key operation unit 152 includes arrowkeys operated to move a cursor and a variety of function keys. A controlsignal representing an operation input entered by the user via the keyoperation unit 152 is supplied to the control unit 14 by way of theinput I/F 151. Thus, in accordance with the control signal, the server 1carries out processing according to the operation input entered by theuser.

The display unit 154 is an output unit for displaying an image. Thedisplay unit 154 receives a video signal to be displayed from thedisplay I/F 153, which is controlled by the control unit 14, anddisplays a variety of pictures on a screen of its own in accordance withthe received video signal.

The external I/F 155 is a unit for controlling operations to exchangedata with an external apparatus connected to the external input/outputterminal 156. To be more specific, when the server 1 outputs data to theexternal apparatus, the external I/F 155 reshapes the data in an outputformat determined in advance and outputs the reshaped data to theexternal apparatus by way of the external input/output terminal 156. Inaddition, the external I/F 155 converts data received in a predeterminedformat from an external apparatus through the external input/outputterminal 156 into data in a format presentable to the control unit 14and supplies the data obtained as a result of the conversion to thecontrol unit 14.

It is to be noted that the server 1 is typically implemented as apersonal computer. In this case, the key operation unit 152 includes akeyboard and a mouse pointer whereas the display unit 154 is a CRT(Cathode Ray Tube) or an LCD (Liquid Crystal Display). In addition, byproviding the personal computer with additional components such asreproduction units for CDs and DVDs or recording/reproduction units forrecordable CDs and recordable DVDs, the personal computer is capable ofreading out data from these CDs and DVDs and utilizing the data as wellas capable of writing data onto the recordable CDs and recordable DVDs.It is to be noted that the additional components are not shown in thefigure.

FIG. 5 is a block diagram showing the internal configuration of thecommunication unit 12. As shown in FIG. 5, the communication unit 12includes a communication I/F 111 and a control unit 112. The controlunit 112 includes a CPU 121, a ROM 122, a RAM 123, a flash memory 124and a bus I/F 125, which are connected to each other by an internal bus126. It is to be noted that the communication I/F 111 is also connectedto the internal bus 126 and controlled by the CPU 121 through theinternal bus 126.

Controlled by the control unit 112, the communication I/F 111 carriesout processing such as a process to convert data received from the LAN 6through the communication terminal 11 in a predetermined format intodata with a format that can be processed by the server 1, and supply thedata obtained as a result of the conversion to the main control unit 14by way of the bus I/F 125. In addition, the communication I/F 111 alsocarries out processing such as a process to convert data to betransmitted from the server 1 to another apparatus connected to the LAN6 into data having a transmission format and output the data having atransmission format to the LAN 6 by way of the communication terminal11. Controlled by the control unit 112 employed in the communicationunit 12, the communication I/F 111 carries out processing conforming tothe Ethernet. The processing includes a process to detect theexistence/non-existence of data on the LAN 6 and detect collisionsbetween transmitted data or transmitted packets. The process to detectthe existence/non-existence of data on the LAN 6 is referred to asdetection of a carrier.

The ROM 122 employed in the control unit 112 is a memory for storingprograms to be executed by the CPU 121 and data required in processing.The RAM 123 is a memory mainly used as a work area in various kinds ofprocessing. The flash memory 124 is a rewritable nonvolatile memory usedfor storing and holding data such as a variety of set parametersrelevant to communication.

In the configuration described above, the server 1 is connected to theLAN 6 through the communication unit 12 and the communication terminal11. The communication unit 12 implements UPnP functions, which allow theserver 1 to be connected to the LAN 6 and data to be exchanged withanother apparatus by way of the LAN 6 in various kinds of processing. Toput it concretely, the server 1 is capable of receiving data transmittedto itself by way of the LAN 6 and storing the data in a memory such asthe HDD 13. In addition, in accordance with a request received from anapparatus serving as a partner as a request for presentation of desireddata, the server 1 is also capable of reading out the desired data froma memory such as the HDD 13 and transmitting the data to the partnerapparatus by way of the communication unit 12, the communicationterminal 11 and the LAN 6.

It is to be noted that, since the server 2 is implemented into the sameconfiguration as the server 1 described above, the explanation of theserver 2 is omitted.

[Typical Configuration of the Audio Reproduction Apparatus]

FIG. 6 is a block diagram showing a typical configuration of the audioreproduction apparatus 3.

As shown in FIG. 6, the audio reproduction apparatus 3 includes acommunication terminal 31, a communication unit 32, a digital inputterminal 33, a digital I/F 34, an analog input terminal 35, ananalog/digital (A/D) conversion unit 36, a selector 37, an equalizer 38,a digital/analog (D/A) conversion unit 39, an audio amplifier 40, aspeaker 41, a control unit 50, an input I/F 61, a key operation unit 62,a display I/F 63, a display unit 64 and a remote-controlleroptical-signal reception unit 65.

The control unit 50 is a microcomputer for controlling other componentsemployed in the audio reproduction apparatus 3. The control unit 50includes a CPU 51, a ROM 52, a RAM 53, an EEPROM 54 and a flash memory55, which are connected to each other by a CPU bus 56.

The ROM 52 is a memory for storing programs to be executed by the CPU 51and data required in processing. The RAM 53 is a memory mainly used as awork area in various kinds of processing. The EEPROM 54 is the so-callednonvolatile memory used for storing various kinds of data that should bekept even if the power supply of the audio reproduction apparatus 3 isturned off. The flash memory 55 is a rewritable nonvolatile memory usedfor storing and holding data such as a variety of set parametersrelevant to communication.

It is to be noted that the communication unit 32, the digital I/F 34,the analog/digital (A/D) conversion unit 36, the selector 37, theequalizer 38, the digital/analog (D/A) conversion unit 39, the audioamplifier 40, the input I/F 61, the display I/F 63 and theremote-controller optical-signal reception unit 65 are also connected tothe CPU bus 56 and controlled by the CPU 51 through the CPU bus 56.

Much like the communication unit 12 employed in the server 1, thecommunication unit 32 implements UPnP functions, which allow the audioreproduction apparatus 3 to be connected to the LAN 6 and data to beexchanged with another apparatus by way of the LAN 6 in various kinds ofprocessing. For example, the communication unit 32 converts datatransmitted to the audio reproduction apparatus 3 itself from the LAN 6by way of the communication terminal 31 into data that can be processedby the audio reproduction apparatus 3. If the data transmitted to theaudio reproduction apparatus 3 itself is audio data, the data issupplied to the selector 37 at a later stage. If data transmitted to theaudio reproduction apparatus 3 itself is control data, on the otherhand, the data is supplied to the control unit 50. In addition,controlled by the control unit 50, the communication unit 32 creates acommand to be transmitted to a desired electronic apparatus andtransmits the command to the desired electronic apparatus by way of theLAN 6. The communication unit 32 also carries out processing conformingto the Ethernet. Examples of the processing are detection of carriersand detection of collisions as described earlier.

The digital input terminal 33 is a component for receiving digital audiodata from a variety of digital-information-processing apparatusinstalled outside the audio reproduction apparatus 3. The digital I/F 34is a component for converting the digital data supplied to the digitalinput terminal 33 into data that can be processed by the audioreproduction apparatus 3 and supplying the data obtained as a result ofthe conversion to the selector 37.

The analog input terminal 35 is a component for receiving digital audiodata from a variety of audio apparatus installed outside the audioreproduction apparatus 3. The A/D conversion unit 36 is a component forconverting the audio data supplied to the analog input terminal 35 intodigital data having a predetermined format and supplying the digitaldata obtained as a result of the conversion to the selector 37.

The selector 37 is a component for selecting audio data supplied by thecommunication unit 32, the digital I/F 34 or the A/D conversion unit 36and supplies the selected audio data to the equalizer 38. The selector37 selects audio data in accordance with a command entered by the uservia a key operation unit 62 and the input I/F 61 or via an externalremote controller 70 and the remote-controller optical-signal receptionunit 65.

The equalizer 38 is a component for carrying out audio-qualityadjustment on the audio data received from the selector 37 andoutputting the result of the adjustment to the D/A conversion unit 39.The user enters parameters of the audio-quality adjustment to thecontrol unit 50 via the key operation unit 62 and the input I/F 61. Thecontrol unit 50 passes on the parameters to the equalizer 38.

The D/A conversion unit 39 is a component for converting the digitalaudio data received from the equalizer 38 into analog audio data. Theaudio amplifier 40 is a component for amplifying the analog datareceived from the D/A conversion unit 39 to a predetermined level andoutputting the result of the amplification to the speaker 41. Thespeaker 41 is a component for generating a sound according to the analogaudio signal supplied thereto by the audio amplifier 40.

It is to be noted that the functions of the equalizer 38 and the D/Aconversion unit 39 can also be implemented by software executed by thecontrol unit 50.

The key operation unit 62 is connected to the control unit 50 throughthe input I/F 61. The input I/F 61 has a variety of operation keys to beoperated by the user to enter an operation input. The key operation unit62 then generates a control signal representing the operation input andsupplies the signal to the control unit 50 by way of the input I/F 61.

The display unit 64 is connected to the control unit 50 through thedisplay I/F 63. The display unit 64 is a display unit implementedtypically by an LCD or an organic EL (Electro-Luminescence) device. Thedisplay unit 64 shows various kinds of display information such as aguidance message, an error message and status in accordance with adisplay signal received from the display I/F 63.

The remote-controller optical-signal reception unit 65 is a componentfor receiving typically an infrared signal from the external remotecontroller 70, converting the infrared signal into an electrical signaland supplying the electrical signal to the control unit 50. The remotecontroller 70 has a variety of operation keys to be operated by the userto enter an operation input, and generates a signal representing theoperation input.

It is to be noted that, since the other audio reproduction apparatus 4and 5 each have the same configuration as the audio reproductionapparatus 3, their descriptions are omitted.

[Operations of the Home Network]

In the home network system described above, when the user desires anaudio content stored in any of the server 1 and 2 each serving as amedia server to be reproduced in any of the audio reproduction apparatus3 to 5 each serving as a media renderer, normally, it is necessary toexecute a processing procedure like one described as follows.

The processing procedure includes the following three steps of:

(1): selecting a server holding a desired audio content.(2): specifying the desired audio content.(3): selecting an audio reproduction apparatus to reproduce the desiredaudio content.

It is to be noted that, in the case of the home network systemimplemented by this embodiment, a plurality of servers and a pluralityof audio reproduction apparatus coexist. Thus, above steps (1) to (3) ofthe procedure must be executed. If only one server exists, however, step(1) of selecting a server holding a desired audio content is notnecessary. By the same token, if only one audio reproduction apparatusexists, step (3) of selecting an audio reproduction apparatus toreproduce a desired audio content is also not necessary.

In addition, the processing procedure may vary from case to case independence on which apparatus includes a control point. If the controlpoint is implemented in a specific audio reproduction apparatus, forexample, the specific audio reproduction apparatus is normally selectedas the apparatus to reproduce the desired audio content. The selectionof such an audio reproduction apparatus is a natural step. Thus, in thiscase, it is not necessary to specially select an audio reproductionapparatus to reproduce the desired audio content. If the control pointis implemented in a specific server, on the other hand, the specificserver is selected as the apparatus containing the desired audio contentin many cases. Thus, the step of selecting a server holding the desiredaudio content can be omitted.

In the conventional home network system, in general, by executing abovesteps (1) to (3) of the procedure, a desired audio content stored in aselected server can be reproduced in a selected audio reproductionapparatus. Since processing such as an operation to select an audiocontent to be reproduced in a specific audio reproduction apparatus iscarried out by operating the specific audio reproduction apparatusitself, however, it is difficult to control operations to start and stopdistribution of an audio content to a plurality of particular audioreproduction apparatus and an operation to reproduce the audio contentin these particular audio reproduction apparatus by merely operating oneaudio reproduction apparatus.

In order to solve this problem, in the home network system implementedby this embodiment, by operating only any one specific audioreproduction apparatus, it is possible to control an operation todistribute an audio content from a server and content reproductionoperations of not only this specific audio reproduction apparatus, butalso other audio reproduction apparatus and, hence, possible to switchan operation to reproduce the audio content from one audio reproductionapparatus to another among a plurality of audio reproductionapparatuses. To put it concretely, an apparatus functioning as a controlpoint is capable of changing distribution destinations of an audiocontent from a media server and controlling operations carried out by aplurality of media renderers to reproduce the content.

[Typical Operations 1: Operating a Content Reproduction Apparatus inOperation to Change the Content Reproduction Apparatus] 1-1: BasicOperations

First of all, by referring to FIG. 7, the following description explainsa case in which typical basic operations are carried out on an audioreproduction apparatus currently reproducing an audio content asoperations to switch a process to reproduce the audio content from theaudio reproduction apparatus reproducing the audio content to another.FIG. 7 is an explanatory diagram showing an outline of the operationscarried out in this case in the whole home network system.

In the explanatory diagram of FIG. 7, in a state where an audio contentdistributed by the server 1 is received and reproduced by the audioreproduction apparatus 3, an operation input is entered to the audioreproduction apparatus 3 currently reproducing the audio content inorder to switch the operation to reproduce the audio content from theaudio reproduction apparatus 3 to the audio reproduction apparatus 4 soas to allow the same audio content reproduced so far to be reproducedcontinuously.

Assume for example that the audio reproduction apparatus 3 and 4 areinstalled in different rooms, and the user who has been listening to apiece of music so far from the audio reproduction apparatus 3 installedin a specific room moves to another room and desires to listen to thecontinuation of the piece of music listened to so far from the audioreproduction apparatus 4 installed in the other room. In this case, acapability of operating the audio reproduction apparatus 3 installed inthe specific room in order to switch the operation to reproduce thepiece of music from the audio reproduction apparatus 3 to the audioreproduction apparatus 4 is considered to be most natural to the user.

In the case described above, the server 1 functions as a media serverwhile the audio reproduction apparatus 3 and 4 each serve as a mediarenderer. In addition, the server 1 requires a control-point function tocontrol the operation to distribute an audio content whereas the audioreproduction apparatus 3 and 4 each require a control-point function tocontrol the operation to reproduce the content. In this embodiment, allapparatus connected to the LAN 6 have all the aforementioned functionsof the control point. Thus, by operating any one of the apparatus as acontrol point, the capability described above can be realized.

In the following description, the audio reproduction apparatus 3receiving an operation input to switch the operation to reproduce thepiece of music from the audio reproduction apparatus 3 to the audioreproduction apparatus 4 functions as a control point. In this case, theaudio reproduction apparatus 3 functioning as a control point is thuscapable of controlling the operation carried out by the server 1 todistribute the piece of music, the operation carried out by the audioreproduction apparatus 3 itself to reproduce the piece of music and theoperation carried out by the audio reproduction apparatus 4 to reproducethe piece of music.

In a simplest operation procedure, first of all, the user enters anoperation input to the audio reproduction apparatus 3 installed in thespecific room from which the user is going to move to designate theaudio reproduction apparatus 4 in the other room as a new transmissiondestination of the audio content. To put it more concretely, at thattime, the audio reproduction apparatus 3 itself is specified as a mediarenderer to end the operation of reproducing the audio content while theaudio reproduction apparatus 4 is newly designated as a media rendererto start an operation of reproducing the audio content. In addition, theserver 1 is specified as a media server functioning as the source of theoperation to transmit the audio content. In this embodiment, however,the audio reproduction apparatus 3 recognizes that the audioreproduction apparatus 3 itself is currently reproducing the audiocontent and the server 1 is functioning as the source of the operationto transmit the audio content. Thus, the user merely needs to carry outonly an operation to newly designate the audio reproduction apparatus 4as a media renderer.

When the user carries out such an operation, the audio reproductionapparatus 3 requests the server 1 to change the destination of theoperation to transmit the audio content from the audio reproductionapparatus 3 to the audio reproduction apparatus 4. At the same time, theaudio reproduction apparatus 3 ends the operation carried out by itselfto reproduce the audio content and requests the audio reproductionapparatus 4 to start an operation to receive and reproduce the audiocontent.

At a request made by the audio reproduction apparatus 3, the server 1stores the data of the audio content being transmitted in a packetdestined for the audio reproduction apparatus 4 and outputs the packetto the LAN 6. At the same time, the server 1 ends the transmission ofpackets of the audio content to the audio reproduction apparatus 3. Inaddition, the audio reproduction apparatus 3 also terminates theoperation to reproduce the audio content whereas the audio reproductionapparatus 4 starts an operation to receive and reproduce datatransmitted by the server 1 in accordance with a control signal receivedfrom the audio reproduction apparatus 3.

In the processing described above, by operating only the audioreproduction apparatus 3 installed in the specific room, the user iscapable of switching the operation to reproduce the audio data from theaudio reproduction apparatus 3 to the audio reproduction apparatus 4 sothat, in the other room, the user can listen to the continuation of thepiece of music listened to so far in the specific room. It is thuspossible to realize a high degree of operatability to switch theoperation to reproduce an audio content from one audio reproductionapparatus to another.

1-2: More Desirable Operations

When an operation to reproduce a piece of music must be switched fromthe audio reproduction apparatus 3 installed in a specific room to theaudio reproduction apparatus 4 installed in another room to accompany amovement of the user from the specific room to the other room asdescribed above, it is more desirable for the user to allow the audioreproduction apparatus 3 to automatically continue its operation toreproduce the piece of music for a predetermined period of timefollowing the process of switching the operation to reproduce the pieceof music from the audio reproduction apparatus 3 to the audioreproduction apparatus 4. In this case, in the predetermined period oftime which is an overlap period of time, both the audio reproductionapparatus 3 installed in the pre-movement specific room and the audioreproduction apparatus 4 installed in the post-movement other roomreproduce the same piece of music concurrently in a synchronous manner.Thus, the user can listen to the piece of music without interruptionwhile the user is moving from the specific room to the other room.

In order to implement the operations described above, the audioreproduction apparatus 3 operating as a control point is required tohave a function for managing content distribution start and end timesfor each distribution destination as a function of a media server aswell as controlling reproduction operations carried out in mediarenderers synchronously with the content distribution start and endtimes. In addition, the server 1 serving as a media server is requiredto have a function to synchronously distribute the same content at thesame time to a plurality of media renderers under control executed by acontrol point.

In addition, in the operation described above, while both the audioreproduction apparatus 3 installed in a specific room and the audioreproduction apparatus 4 installed in the other room are reproducing thesame piece of music, the volume of a sound reproduced in thepre-movement specific room can be gradually reduced to make the soundgradually fade out while the volume of a sound reproduced in thepost-movement other room can be gradually increased to make the soundgradually fade in. In this way, the user can continue listening to thepiece of music with a natural sense having a low degree ofincompatibility. In order to implement such an operation, for example,it is nice to prescribe a control command to be issued by a controlpoint to a media renderer as a command making a request for an operationto control the volume of a sound being reproduced, that is, a requestfor a fade-in or fade-out operation.

The following description explains processing carried out by apparatusto implement the operations described above. First of all, processingcarried out by the audio reproduction apparatus 3 is described. In thefollowing description, the processing carried out by the audioreproduction apparatus 3 is explained by focusing the explanation on thefunction of the audio reproduction apparatus 3 serving as a controlpoint.

FIG. 8 shows a flowchart representing the processing carried out by theaudio reproduction apparatus 3 functioning as a control point. When thepower supply of the audio reproduction apparatus 3 is turned on, thecontrol unit 50 executes a control application program for controllingthe audio reproduction apparatus 3 as a whole. In the controlapplication program, a U/I screen is displayed to the user and, inaccordance with instructions shown on the U/I screen, the user operatesinput units such as the key operation unit 62 and the remote controller70 to control operations of the audio reproduction apparatus 3.

In addition, at that time, functions of the audio reproduction apparatus3 serving as a control point as well as a media renderer are alsoinvoked. An example of these functions is execution of programs otherthan the control application program by a CPU employed in thecommunication unit 32. That is to say, another program executed to allowthe audio reproduction apparatus 3 to function as a control pointreceives input information, which is entered by the user, through thecontrol application program, controls operations carried out by theaudio reproduction apparatus 3 functioning as a media renderer andcontrols operations carried out by a server functioning as a mediaserver and other media renderers through the LAN 6. On the other hand,another program executed to allow the audio reproduction apparatus 3 tofunction as a media renderer controls an operation to reproduce an audiocontent in the audio reproduction apparatus 3 itself through the controlapplication program in accordance with a control command issued by thecontrol point.

Assume here for example that the control application program of an audioreproduction apparatus is executed in accordance with an operation inputentered by the user to cause a transition to an operation mode in whichthe audio reproduction apparatus is capable of receiving an audiocontent transmitted by the server 1 or 2 by way of the LAN 6. In thiscase, the following processing is carried out.

The flowchart shown in FIG. 8 begins with a step S101 at which the audioreproduction apparatus 3 receives an input to select an audioreproduction apparatus to newly start an operation to reproduce an audiocontent. Since the audio reproduction apparatus 3 functioning as acontrol point knows what audio reproduction apparatus are connected tothe network of the home network system, the user can enter the input toselect an audio reproduction apparatus to newly start an operation toreproduce an audio content by typically referring to a list displayed onthe display unit 64 as a list of selectable audio reproductionapparatus.

An audio reproduction apparatus actually receiving the inputinformation, which is the audio reproduction apparatus 3 in theoperations explained earlier by referring to FIG. 7, is assumed to be anaudio reproduction apparatus supposed to reproduce an audio content.Thus, the audio reproduction apparatus 3 can be just set automaticallyas an audio reproduction apparatus to reproduce an audio content at apoint of transition to the operation mode without requiring the user tospecially select such an audio reproduction apparatus at the step S101.

Then, at the next step S102, the audio reproduction apparatus 3 receivesan input to select a server to function as a source of the operation totransmit an audio content and select an audio content to be transmitted.As described above, the audio reproduction apparatus to newly start anoperation to reproduce the selected audio content is the audioreproduction apparatus 3 itself. This audio reproduction apparatus 3functioning as a control point has information on selectable mediaservers and is capable of obtaining information on audio contents storedin each of the media servers by execution of a CDS function. Thus, byexecution of such a function, the audio reproduction apparatus to newlystart an operation to reproduce the selected audio content is capable ofdisplaying the names of the selectable media servers and the titles ofthe audio contents stored in each of the media servers on the displayunit 64 in processing of the control application program. Accordingly,the user can enter the input to select a server to function as a sourceof the operation to transmit an audio content to be distributed byreferring to the pieces of information displayed on the display unit 64.

Then, at the next step S103, the audio reproduction apparatus 3determines whether or not the input received at the step S102 is aninput to select a server to function as a source of the operation totransmit an audio content to be distributed. The user enters such aninput by, for example, selecting icons displayed on the display unit 64.If the audio reproduction apparatus 3 determines that the input receivedat the step S102 is an input to select a server to function as a sourceof the operation to transmit an audio content to be distributed, theflow of the processing goes on to a step S104. If the audio reproductionapparatus 3 determines that the input received at the step S102 is notan input to select a server to function as a source of the operation totransmit an audio content to be distributed, on the other hand, the flowof the processing goes back to the step S102. At the step S102, the useris also allowed to change the input entered previously.

At the step S104, the audio reproduction apparatus 3 informs the server1 serving as the selected media server of the selected audio content andthe audio reproduction apparatus selected to newly start an operation toreproduce the selected audio content. In this case, the selected audioreproduction apparatus to newly start the operation to reproduce theselected audio content is the audio reproduction apparatus 3 itself asdescribed above. As a result, the server 1 transmits the data of theaudio content to the audio reproduction apparatus 3 by way of the LAN 6.

Then, at the next step S105, the audio reproduction apparatus 3 requeststhe audio reproduction apparatus for newly starting an operation toreproduce the selected audio content to start the reproduction. In thiscase, the selected audio reproduction apparatus to newly start anoperation to reproduce the selected audio content is the audioreproduction apparatus 3 itself as described above. As a result, thecommunication unit 32 employed in the audio reproduction apparatus 3receives the data of the audio content from the server 1 and passes onthe data to an audio reproduction functional unit by way of the selector37. The audio reproduction functional unit then reproduces a sound fromthe data.

Then, at the next step S106, the audio reproduction apparatus 3determines whether or not an input to switch the operation to reproducethe audio content from the audio reproduction apparatus reproducing theaudio content to another audio reproduction apparatus has been received.If the audio reproduction apparatus 3 determines that an input to switchthe operation to reproduce the audio content from the audio reproductionapparatus reproducing the audio content to another audio reproductionapparatus has been received, processing of a step S107 is carried out.As an example of determination processing carried out at the step S106,the audio reproduction apparatus 3 displays an icon to be operated toswitch the operation to reproduce the audio content from the audioreproduction apparatus reproducing the audio content to another audioreproduction apparatus on the display unit 64. If the user operates theicon, the audio reproduction apparatus 3 determines that a request hasbeen made as a request for a process of switching the operation toreproduce the audio content from the audio reproduction apparatus 3 toanother audio reproduction apparatus. If the audio reproductionapparatus 3 determines that an input to switch the operation toreproduce the audio content from the audio reproduction apparatusreproducing the audio content to another audio reproduction apparatushas not been received, on the other hand, the flow of the processinggoes on to a step S108.

At the step S107, a subroutine for switching the operation to reproducethe audio content from the audio reproduction apparatus 3 to anotheraudio reproduction apparatus is executed. This subroutine will bedescribed later by referring to a flowchart shown in FIG. 9. When theexecution of this subroutine is completed, the flow of the processinggoes back to the step S106.

At the next step S108, the audio reproduction apparatus reproducing theaudio content determines whether or not an input to terminate thereproduction operation has been received. As an example of the input toterminate the reproduction operation, the user operates areproduction-end button provided on the key operation unit 62. If theaudio reproduction apparatus reproducing the audio content determinesthat an input to terminate the reproduction operation has been received,the flow of the processing goes on to a step S109. If the audioreproduction apparatus reproducing the audio content determines that aninput to terminate the reproduction operation was not received, on theother hand, the flow of the processing goes back to the step S106.

At the step S109, the audio reproduction apparatus reproducing the audiocontent requests the server 1 serving as a media server to terminate theoperation to transmit the audio content to the audio reproductionapparatus. At this request made by the audio reproduction apparatusreproducing the audio content, the server 1 terminates the operation totransmit the audio content which was selected in the processing carriedout at the step S102.

Then, at the next step S110, the audio reproduction apparatusreproducing the audio content is requested to terminate the operation toreproduce the audio content. If the audio reproduction apparatus 3 isreproducing the audio content, the audio reproduction apparatus 3 iscapable of terminating the operation to reproduce the audio content. Ifprocessing was carried out at the step S107 to switch the operation toreproduce the audio content from the audio reproduction apparatus 3 toanother audio reproduction apparatus, a function included in the otheraudio reproduction apparatus as a function of the control point can beused to specify the other audio reproduction apparatus itself as anaudio reproduction apparatus to terminate the operation to reproduce theaudio content. In addition, through the LAN 6, the audio reproductionapparatus 3 is capable of detecting a termination input entered to theother audio reproduction apparatus such as the audio reproductionapparatus 4 currently reproducing the audio content for example andterminating the operation being carried out by the audio reproductionapparatus 4 as the operation to reproduce the audio content inaccordance with the detected termination input.

FIG. 9 shows a flowchart representing the processing carried out by theaudio reproduction apparatus 3 serving as a control point to switch theoperation to reproduce an audio content from the audio reproductionapparatus 3 to another audio reproduction apparatus.

The flowchart begins with a step S201 at which an input specifying anaudio reproduction apparatus as an audio reproduction apparatus toterminate the operation to reproduce an audio content is received. Inthe case of the operations shown in FIG. 7, the audio reproductionapparatus to terminate the operation to reproduce an audio content isassumed to be the audio reproduction apparatus 3 itself. Thus, at thestep S201, the audio reproduction apparatus 3 is automatically specifiedas the audio reproduction apparatus to terminate the operation toreproduce an audio content without requiring the user to specially enteran input specifying an audio reproduction apparatus as an audioreproduction apparatus to terminate the operation to reproduce an audiocontent.

Then, at the next step S202, the audio reproduction apparatus 3 receivesan input specifying an audio reproduction apparatus as an audioreproduction apparatus newly selected as an apparatus to start anoperation of reproducing an audio content. In the case of the operationsshown in FIG. 7, the audio reproduction apparatus 4 is designated as theaudio reproduction apparatus newly selected as an apparatus to start theoperation of reproducing an audio content. At the step S202, typically,a list of other audio reproduction apparatus connected to the network ofthe home network system is displayed on the display unit 64 and the userenters an input specifying an audio reproduction apparatus as an audioreproduction apparatus newly selected as an apparatus to start theoperation of reproducing an audio content by selecting an audioreproduction apparatus from those included on the list. As analternative, information identifying an audio reproduction apparatusdesignated before as an audio reproduction apparatus newly selected asan apparatus to start the operation of reproducing an audio content orinformation indicating an audio reproduction apparatus assumed to be anaudio reproduction apparatus newly selected as an apparatus to start theoperation of reproducing an audio content is stored in advance in theflash memory 55 and the audio reproduction apparatus indicated by theinformation can be designated automatically this time as an audioreproduction apparatus newly selected as an apparatus to start theoperation of reproducing an audio content.

Then, at the next step S203, the audio reproduction apparatus 3 receivesan input indicating a time duration T to the actual execution of theprocess of switching the operation to reproduce an audio content to thenewly selected audio reproduction apparatus to start the operation ofreproducing an audio content. The time duration T can be a minimum of 0.

Subsequently, at the next step S204, the audio reproduction apparatus 3receives an input revealing whether or not fade-in and fade-outoperations are to be carried out.

Then, the flow of the processing goes on to the next step S205 at whichthe audio reproduction apparatus 3 examines the inputs received at thesteps S201 to S204 to verify that the inputs are a request to start aprocess of switching the operation to reproduce an audio content to anaudio reproduction apparatus newly selected as an apparatus to start anoperation of reproducing an audio content. For example, the user maymake a request to change the inputs in some cases. In this case, theflow of the processing goes back to the step S201 to receive new inputs.If the result of the verification reveals that the inputs are a requestto start a process of switching the operation to reproduce an audiocontent to the newly selected audio reproduction apparatus to start theoperation of reproducing an audio content, the flow of the processinggoes on to a step S206.

At the step S206, the audio reproduction apparatus 3 notifies the server1 of the newly selected audio reproduction apparatus specified at thestep S202 as an audio reproduction apparatus to start the operation ofreproducing an audio content. The audio reproduction apparatus newlyselected as an apparatus to start the operation of reproducing an audiocontent is the audio reproduction apparatus 4 in this case. In addition,the audio reproduction apparatus 3 requests the audio reproductionapparatus, which has been newly selected as an apparatus to start theoperation of reproducing an audio content. As a result, the server 1starts transmitting the audio content to the audio reproductionapparatus newly selected as an apparatus to start the operation ofreproducing the audio content. It is to be noted that, at that time, theaudio reproduction apparatus serving as the destination of the operationto transmit the audio content so far and the newly selected audioreproduction apparatus both receive the same audio content concurrently.In this example, the audio reproduction apparatus serving as thedestination of the operation to transmit the audio content so far andthe newly selected audio reproduction apparatus are the audioreproduction apparatus 3 and the audio reproduction apparatus 4respectively as described above.

Then, at the next step S207, the audio reproduction apparatus 3determines whether or not fade-in and fade-out operations have beenspecified at the step S204. If a result of determination reveals thatfade-in and fade-out operations have been specified at the step S204,the flow of the processing goes on to a step S208. If the result ofdetermination reveals that fade-in and fade-out operations were notspecified at the step S204, on the other hand, the flow of theprocessing goes on to a step S209.

At the step S208, the audio reproduction apparatus 3 requests the newlyselected audio reproduction apparatus, which is the audio reproductionapparatus 4 in this case, to start an operation of receiving andreproducing the audio content and, at the same time, start a fade-inoperation. As requested by the audio reproduction apparatus 3, the audioreproduction apparatus 4 serving as the newly selected audioreproduction apparatus sets the volume of an output sound at 0 in aninitial state, starts an operation to reproduce the received audiocontent and then reproduces the content while gradually increasing thevolume of a generated sound till a determination result produced at thefollowing step S210 reveals that the time duration T has lapsed. Then,the flow of the processing goes on to the step S210.

At the step S209, on the other hand, the audio reproduction apparatus 3requests the newly selected audio reproduction apparatus, which is theaudio reproduction apparatus 4 in this case, to start an operation ofreceiving and reproducing the audio content. As requested by the audioreproduction apparatus 3, the audio reproduction apparatus 4 serving asthe newly selected audio reproduction apparatus starts the operation toreproduce the audio content received from the server 1. It is to benoted that, also in this case, the flow of the processing then goes onto the step S210 as well.

At the step S210, the audio reproduction apparatus 3 determines whetheror not the time duration T has lapsed since the start of the step S206by measuring the time duration T on the basis of a counting operation ofa counter in a state of waiting for the time duration T to lapse. If theaudio reproduction apparatus 3 determines that the time duration T haslapsed since the start of the step S206, the flow of the processing goeson to a step S211.

At the step S211, the audio reproduction apparatus 3 examines the inputreceived at the step S204 to determine whether a fade-out operation hasbeen requested. If the input received at the step S204 reveals that afade-out operation has been requested, the flow of the processing goeson to a step S212. If the input received at the step S204 reveals thatno fade-out operation has been requested, on the other hand, the flow ofthe processing goes on to a step S214.

At the step S212, the audio reproduction apparatus 3 requests the audioreproduction apparatus, which was selected at the step S201 as an audioreproduction apparatus to terminate the operation to reproduce an audiocontent, to start the fade-out operation. In this case, the audioreproduction apparatus selected at the step S201 as an audioreproduction apparatus to terminate the operation to reproduce an audiocontent is the audio reproduction apparatus 3 itself. As requested, theaudio reproduction apparatus 3 serving as a media renderer graduallydecreases the volume of a generated sound till a determination resultproduced at the following step S213 reveals that the time duration T haslapsed.

At the step S213, the audio reproduction apparatus terminating theoperation to reproduce an audio content determines whether or not thetime duration T has lapsed since the start of the step S212 by measuringthe time duration T on the basis of a counting operation of a counter ina state of waiting for the time duration T to lapse. If the audioreproduction apparatus terminating the operation to reproduce an audiocontent determines that the time duration T has lapsed since the startof the step S212, the flow of the processing goes on to the step S214.It is to be noted that the time duration of the fade-out operation canbe set at a value equal to or different from that of the fade-inoperation.

At the step S214, the audio reproduction apparatus 3 requests the server1 to end the operation to transmit the audio content to the audioreproduction apparatus terminating the operation to reproduce the audiocontent. In this case, the audio reproduction apparatus terminating theoperation to reproduce the audio content is the audio reproductionapparatus 3 itself as described above. As requested by the audioreproduction apparatus 3, the server 1 ends the operation to transmitthe audio content to the audio reproduction apparatus 3 but continuesthe operation to transmit the audio content to the audio reproductionapparatus 4 only.

Then, at the next step S215, the audio reproduction apparatus 3 requeststhe audio reproduction apparatus terminating the operation to reproducean audio content to end the operation of reproducing the audio content.In this case, the audio reproduction apparatus terminating the operationto reproduce the audio content is the audio reproduction apparatus 3itself as described above. Thus, only the audio reproduction apparatusnewly designated as an audio reproduction apparatus to start theoperation of reproducing an audio content continues the operation toreproduce the audio content. As described above, the audio reproductionapparatus newly designated as an audio reproduction apparatus to startthe operation of reproducing an audio content is the audio reproductionapparatus 4 in this case.

As described above, in accordance with an operation input received fromthe user, the audio reproduction apparatus 3 functioning as a controlpoint as well as a media renderer is capable of controlling an operationcarried out by itself to reproduce an audio content, an operationcarried out by a server to transmit the same audio content to anothermedia renderer and an operation carried out by the other media rendererto reproduce the audio content. Thus, by merely carrying out anoperation only on one audio reproduction apparatus, the user cancontinue listening to the same audio content in another room without aninterruption.

Next, refer to FIG. 10 showing a flowchart representing processingcarried out by the server 1, which functions as a media server.

In the server 1, the control unit 112 employed in the communication unit12 executes a program allowing the server 1 to function as a mediaserver. On the other hand, the control unit 14 executes a controlapplication program for controlling the server 1 as a whole. The controlunit 112 executes the program allowing the server 1 to function as amedia server as requested by a control command received from a controlpoint through the LAN 6 to carry out processing as an operation to readout a content from the HDD 13 through the control application program.

The flowchart begins with a step S301 at which the control unit 14employed in the server 1 executes the control application program,invoking the function of a media server to monitor packets in the LAN 6in order to determine whether a packet destined for the server 1 itselfhas been transmitted by a control point implemented by the audioreproduction apparatus 3 in this case. As a packet destined for theserver 1 itself is received, the flow of the processing goes on to astep S302.

At the step S302, the server 1 examines the received packet to determinewhether or not the packet is a packet requesting the server 1 to startthe operation to transmit an audio content to an audio reproductionapparatus. If the server 1 determines that the packet is a packetrequesting the server to start transmission of a desired audio contentto an audio reproduction apparatus, the flow of the processing goes onto a step S303. If the server 1 determines that the packet is not apacket requesting the server to start transmission of a desired audiocontent to an audio reproduction apparatus, on the other hand, the flowof the processing goes on to a step S307.

At the step S303, the server 1 determines whether or not the server 1itself is currently transmitting the desired audio content. If theserver 1 determines that the server 1 itself is not currentlytransmitting the desired audio content, the flow of the processing goeson to a step S304. If the server 1 determines that the server 1 itselfis currently transmitting the desired audio content, on the other hand,the flow of the processing goes on to a step S306.

At the step S304, the server 1 recognizes the desired audio content tobe transmitted to the audio reproduction apparatus, which is specifiedin the packet received from the control point. To put it concretely, theserver 1 fetches information identifying the desired audio packet fromthe packet.

Then, at the next step S305, the server 1 reads out the data of thedesired audio content recognized at the step S304 from the HDD 13 andsequentially transmits the data to the audio reproduction apparatusspecified in the packet by way of the LAN 6. In this case, the audioreproduction apparatus specified in the packet is the audio reproductionapparatus 3. Thus, the desired audio content is reproduced in the audioreproduction apparatus 3. Then, the flow of the processing goes back tothe step S301 to enter a state of waiting for a packet specifying atransmission destination and a desired audio packet to be transmitted bya control point.

At the step S306, on the other hand, the server 1 transmits the sameaudio content as an audio content currently being transmitted at thesame time to the audio reproduction apparatus specified in the packetreceived from the control point. It is to be noted that the server 1transmits the same audio content to the destination audio reproductionapparatus with a synchronous transmission timing, which can be set bytypically referring to a time code of the audio content. Then, the flowof the processing goes back to the step S301 to enter a state of waitingfor a packet specifying a transmission destination and a desired audiopacket to be transmitted by a control point.

Normally, the flow of the processing goes on from the step S303 to thesteps S304 and S305 when the processing is carried out for the firsttime. For example, the audio reproduction apparatus serving as thedestination of the process carried out at the steps S304 and S305 totransmit a desired audio content is the audio reproduction apparatus 3functioning as a media renderer as described above. When audioreproduction apparatus 4 is specified newly as an audio reproductionapparatus to replace the audio reproduction apparatus 3 as explainedearlier by referring to the operations shown in FIG. 7, the switchingprocess is carried out again. For the switching process carried out thistime, however, the flow of the processing goes on from the step S303 tothe step S306 to transmit the same desired audio content also to theaudio reproduction apparatus 4 at the same time so that the audioreproduction apparatus 3 and the audio reproduction apparatus 4 arecapable of reproducing the audio content concurrently.

At the step S307, the server 1 examines the received packet to determinewhether or not the received packet is a packet specifying an audioreproduction apparatus and requesting the server 1 to terminate currentthe operation to transmit an audio content to the specified audioreproduction apparatus. If the server 1 determines that the receivedpacket is a packet specifying an audio reproduction apparatus andrequesting the server 1 to terminate current the operation to transmitan audio content to the specified audio reproduction apparatus, the flowof the processing goes on to a step S309. If the server 1 determinesthat the received packet is not a packet specifying an audioreproduction apparatus and requesting the server 1 to terminate currentthe operation to transmit an audio content to the specified audioreproduction apparatus, on the other hand, the flow of the processinggoes on to a step S308.

At the step S308, the server 1 carries out processing according to thereceived packet. Then, the flow of the processing goes back to the stepS301 to enter a state of waiting for a packet specifying a transmissiondestination and a desired audio packet to be transmitted by a controlpoint.

At the step S309, on the other hand, the server 1 terminates the currentoperation to transmit an audio content to the specified audioreproduction apparatus, which is the audio reproduction apparatus 3 inthis case. Then, at the next step S310, the server 1 determines whetheror not any audio reproduction apparatus is receiving a transmitted audiocontent. If the server 1 determines that an audio reproduction apparatusis receiving a transmitted audio content, the flow of the processinggoes back to the step S301 to enter a state of waiting for a packetspecifying a transmission destination and a desired audio packet to betransmitted by a control point. If the server 1 determines that no audioreproduction apparatus is receiving a transmitted audio content, on theother hand, the execution of the processing is ended.

By executing the processing described above, the server 1 functioning asa media server is capable of transmitting the same audio content to aplurality of audio reproduction apparatus each serving as a mediarenderer and switching the operation to transmit an audio content fromone media renderer to another in accordance with a control commandreceived from one of the media renderers, which are each an audioreproduction apparatus. Thus, the server 1 is capable of changing thedestination of the operation to transmit an audio content under controlexecuted by an audio reproduction apparatus, which usually serves as thecontent transmission destination. In addition, the server 1 may berequested to terminate the operation to transmit an audio content to anaudio reproduction apparatus serving as a media renderer so far after atime duration has lapsed since the start of the operation to transmitthe audio content to an audio reproduction apparatus newly designated asa media renderer. In this case, during the time duration, the same audiocontent is transmitted simultaneously to both the audio reproductionapparatus serving as a media renderer so far and the audio reproductionapparatus newly designated as a media renderer.

The following description explains transmission of the same audiocontent from a media server to a plurality of audio reproductionapparatus each serving as a media renderer at the same time in moredetail. When the same audio content is transmitted to a plurality ofaudio reproduction apparatus, the media server is capable of making selfadjustments so as to allow the audio reproduction apparatus to reproducethe audio content as synchronously as possible with a highest possibledegree of accuracy. Typically, the media server is capable oftransmitting the audio content to the audio reproduction apparatus byshifting timings to transmit the audio content to the audio reproductionapparatus in accordance with the characteristics of each of the audioreproduction apparatus and the environment for generating the audiocontent.

For example, the media server transmits a predetermined command to anaudio reproduction apparatus, which serves as a destination of theoperation to transmit an audio content, by executing a ping program andmeasures time lapsing since the operation to transmit the audio contenttill a response to the command is received from the audio reproductionapparatus. In this way, the media server is capable of obtaining thelength of time it takes to propagate an audio content to the audioreproduction apparatus. On the basis of results of such measurements,the media server is capable of adjusting timings to transmit an audiocontent to audio reproduction apparatus so as to establishsynchronization of operations carried out by the audio reproductionapparatus to reproduce the audio content. In this case, the media serveris capable of compensating for reproduction synchronization shifts ofthe order of typically several milliseconds to several tens ofmilliseconds.

In addition, an audio content stored in a memory such as an HDD employedin a media server may be compressed data. In this case, prior to anoperation to transmit the audio content to an audio reproductionapparatus, the media server reads out the audio data of the content fromthe memory, decodes the data of the content by decompressing the dataand puts data obtained as a result of the decompression in a packetdestined for the audio reproduction apparatus. Then, the media serveroutputs the packet to the LAN 6. In the process to put the audio contentin a packet, typically, the media server activates a decode engine foreach audio reproduction apparatus to receive the audio content and putsthe content data obtained as a result of decode processing carried outby the decode engine in a packet destined for the audio reproductionapparatus associated with the decode engine. However, this method causesthe media server to bear a heaviest processing load. In order to reducethe processing load, content data obtained as a result of decodeprocessing carried out by a decode engine common to all audioreproduction apparatus is transmitted to each of the audio reproductionapparatus.

In addition, the processing to decode the audio data can be carried outin each audio reproduction apparatus. In this case, the processing loadborne by the media server can be further reduced and the amount of datatransmitted from the media server to the audio reproduction apparatus byway of the LAN 6 also becomes smaller as well.

Next, refer to FIG. 11, which shows a flowchart representing aprocessing procedure executed by an audio reproduction apparatus servingas a media renderer. The flowchart shown in FIG. 11 also revealsprocessing functions to be provided to all the audio reproductionapparatus 3 to 5, which each serve as a media renderer. If each of theaudio reproduction apparatus 3 to 5 is capable of executing such aprocessing procedure, it is possible to realize a process of switchingan operation to reproduce an audio content from one audio reproductionapparatus to another.

An audio reproduction apparatus serving as a media renderer receives acontrol command from a control point through the LAN 6 as a command tostart or end an operation to reproduce an audio content as well as acommand to carry out a fade-in or fade-out operation. In the operationsshown in FIG. 7, the audio reproduction apparatus 4 serving as a mediarenderer receives a control command from a control point through the LAN6 as a command to start an operation of reproducing an audio content bycarrying out a fade-in operation. On the other hand, the audioreproduction apparatus 3 serving as a media renderer receives a controlcommand from a program executed to implement functions of a controlpoint as a command to end an operation of reproducing an audio contentby carrying out a fade-out operation.

The flowchart begins with a step S401 at which the audio reproductionapparatus enters a state of waiting for a command to be issued by acontrol point as a command to reproduce an audio content. As such acommand is received, the flow of the processing procedure goes on to astep S402.

At the step S402, the audio reproduction apparatus determines whether ornot the command also includes a request for a fade-in operation. If thecommand also includes a request for a fade-in operation, the flow of theprocessing procedure goes on to a step S403. If the command does notinclude a request for a fade-in operation, on the other hand, the flowof the processing procedure goes on to a step S404.

At the step S403, the audio reproduction apparatus sets the reproductionvolume of the audio content at an initial value of 0, from which thevolume is to be gradually increased. At the step S404, the audioreproduction apparatus receives the audio content from the server 1 andstarts an operation to reproduce the content. Thus, if a fade-inoperation is not specified in the command, the operation to reproducethe audio content is started immediately at the present set volume, forexample.

Then, at the next step S405, the audio reproduction apparatus determineswhether or not the command also includes a request for a fade-outoperation. If the command also includes a request for a fade-outoperation, the flow of the processing procedure goes on to a step S406.If the command does not include a request for a fade-out operation, onthe other hand, the flow of the processing procedure goes on to a stepS407.

At the step S406, the audio reproduction apparatus decreases the volumeof the reproduced audio content gradually. At the step S407, the audioreproduction apparatus determines whether or not a command to end theoperation of reproducing the audio content has been received from acontrol point. If the audio reproduction apparatus determines that acommand to end the operation of reproducing the audio content has beenreceived from a control point, the flow of the processing procedure goeson to a step S408. If the audio reproduction apparatus determines that acommand to end the operation of reproducing the audio content has notbeen received from a control point, the flow of the processing proceduregoes back to the step S405. It is to be noted that, if the determinationresult produced at the step S405 reveals that the command also includesa request for a fade-out operation, normally, a command to end theoperation of reproducing the audio content is received from a controlpoint after the lapse of time it takes to reduce the volume of thereproduced audio content gradually to 0.

At the step S408, the audio reproduction apparatus ends the operation toreceive the audio content from the server 1 and the operation toreproduce the received content.

The processing described above is compared with the operations shown inFIG. 7 as follows. The process carried out at the step S401 correspondsto the operations carried out by the audio reproduction apparatus 4serving as an apparatus, which is newly designated as an audioreproduction apparatus to start the operation of reproducing an audiocontent, to monitor a packet from the audio reproduction apparatus 3serving as a control point and receive a command included in the packetas a command to start the operation of reproducing the audio contentwith a predetermined timing. The process carried out at the step S404corresponds to the operations carried out by the audio reproductionapparatus 4 to receive the audio content from the server 1 and reproducethe received content. The process carried out at the step S402corresponds to the operation carried out by the audio reproductionapparatus 4 to determine whether or not the command includes a requestfor a fad-in operation. The process carried out at the step S403corresponds to the operation carried out by the audio reproductionapparatus 4 to set the reproduction volume of the audio content at aninitial value of 0, from which the volume is to be gradually increasedin the process carried out at the step S404.

In this case, the flow of the processing procedure goes on from the stepS404 to the step S407 by way of the step S405, skipping the step S406.The process carried out at the step S407 corresponds to an operationcarried out by the audio reproduction apparatus 4 to receive a commandfor ending the operation to reproduce the audio content in the audioreproduction apparatus 4 itself. The command is typically an operationinput entered to the audio reproduction apparatus 3 to request the audioreproduction apparatus 3 serving as a control point to give a controlcommand to the audio reproduction apparatus 4 to end the operation ofreproducing the audio content in the audio reproduction apparatus 4. Asan alternative, the control-point function of the audio reproductionapparatus 4 is used. In this case, the command is an operation inputentered to the audio reproduction apparatus 4 itself as a commanddirectly requesting the audio reproduction apparatus 4 to end theoperation of reproducing the audio content in the audio reproductionapparatus 4.

By the way, the process carried out at the step S401 can also correspondto the operation carried out by the audio reproduction apparatus 3serving as an audio reproduction apparatus, from which the operation toreproduce an audio content is to be switched to the audio reproductionapparatus 4, to detect a command received from the function of thecontrol point of its own as a command to start the operation ofreproducing the audio content. In this case, the flow of the processingprocedure goes on from the step S401 to the step S404 by way of the stepS402, skipping the step S403. The process carried out at the step S404corresponds to the operations carried out by the audio reproductionapparatus 3 to receive the audio content from the server 1 and reproducethe received content. The process carried out at the step S405corresponds to the operation carried out by the audio reproductionapparatus 3 to determine whether or not the command includes a requestreceived from the control point as a request for a fad-out operation tobe carried out for the duration of a predetermined time. The processcarried out at the step S406 corresponds to the operation carried out bythe audio reproduction apparatus 3 to gradually decrease the volume ofthe audio content being reproduced. The process carried out at the stepS407 corresponds to the operation carried out by the audio reproductionapparatus 3 to receive a command from the control point as a command toterminate the operation to reproduce the audio content as the volume ofaudio content being reproduced becomes 0.

In either case, the process carried out at the step S408 corresponds tothe operation carried out by the audio reproduction apparatus 4 or 3 toterminate the operation to reproduce the audio content.

As described above, not only is an audio reproduction apparatus servingas a media renderer capable of carrying out an operation to reproduce anaudio content in accordance with an operation input entered by the userto the audio reproduction apparatus itself, but the audio reproductionapparatus also has the operation controlled by control informationreceived from another apparatus existing in the home network system.Thus, by giving an operation to only one media renderer, it is possibleto switch an operation to reproduce an audio content from one audioreproduction apparatus to another.

The following description is a supplementary description explainingfade-in and fad-out control. In order to request an audio reproductionapparatus to carry out a fade-in or fade-out operation, a control pointissues a control command making a request for the fade-in or fade-outoperation to the audio reproduction apparatus. Typically, the controlcommand specifies the time duration of the fade-in or fade-outoperation. This time duration corresponds to the time duration T shownin FIG. 9. Thus, the audio reproduction apparatus is capable ofcomputing the increasing or decreasing speed of the volume from thepresent set volume and the time duration T, and increasing or decreasingspeed the volume at the computed speed. In the case of a fade-inoperation, a maximum volume may be specified from the control point.

As an alternative, the control point issues a control command to theaudio reproduction apparatus as a command specifying a volume-increasingor decreasing speed computed by the control point. In this way, theaudio reproduction apparatus is also capable of generating a sound witha volume varying with the lapse of time in the fade-in or fade-outoperation.

As another alternative, the control point issues a control command tothe audio reproduction apparatus as a command indicating whether or nota fade-in or fade-out operation is to be carried out. In this case, theaudio reproduction apparatus finds an increasing or decreasing speed ofthe volume and a maximum volume by itself in dependence on the state ofprocessing in the audio reproduction apparatus. Thus, the length of thefade-in or fade-out operation may not match the time duration T.

By carrying out the pieces of processing represented by the flowchartsshown in FIGS. 8 to 11, it is possible to perform a process of switchingan operation to reproduce an audio content from one audio reproductionapparatus to another with a high degree of operatability. That is tosay, the user merely sets a specific one of audio reproduction apparatuson which the process of switching the operation to reproduce an audiocontent is to be carried out and, when the process is implemented uponcompletion of a setting operation carried out by the user on thespecific audio reproduction apparatus, the operation carried out by theaudio reproduction apparatus newly designated as a media renderer tooutput the audio content is started. In the example described above, theaudio reproduction apparatus from which the process of switching theoperation to reproduce an audio content to another audio reproductionapparatus is carried out is the audio reproduction apparatus 3 whereasthe audio reproduction apparatus newly designated as a media renderer tooutput the audio content is the audio reproduction apparatus 4. With theaudio reproduction apparatus 3 set in this condition, when the userleaves a specific room in which the audio reproduction apparatus 3 isinstalled and moves to another room of the audio reproduction apparatus4, the user can listen to the continuation of the audio content listenedto so far. Then, as the time duration T lapses, the operation carriedout by the audio reproduction apparatus 3 to reproduce the audio contentin the specific room is ended automatically. Thus, the user needs onlyto operate the audio reproduction apparatus 3 before moving to the otherroom to be able to continue listening to the same audio content. As aresult, convenience offered to the user is enhanced.

If neither fade-in operation nor fade-out operation is specified in therequest to switch the operation to reproduce an audio content from oneaudio reproduction apparatus to another, the same audio content isreproduced in the specific and other rooms at the same time at a normalvolume while the user is moving from the specific room to the otherroom. Thus, the user can continuously listen to the audio content in thenatural sense without an interruption to the state of being able to hearthe audio content. If both a fade-in operation and a fade-out operationare specified in the request, on the other hand, as the user leaves thespecific room and approaches the other room, the volume of the audiocontent reproduced in the other room is increased gradually and, whenthe user is about to arrive at the other room, the volume of the audiocontent reproduced in the specific room is decreased, approaching 0.Thus, the user can continue listening to the audio content in a morenatural sense.

[Typical Operations 2: Operating a Newly Designated Content ReproductionApparatus to Change a Content Reproduction Apparatus in Operation]

By the way, the process of switching the operation to reproduce an audiocontent from an audio reproduction apparatus to another can be carriedout in not only the audio reproduction apparatus currently reproducingthe audio content, but also the audio reproduction apparatus to whichthe operation to reproduce the audio content is to be switched. As aconceivable example, the user desires to listen to an audio content,which is being reproduced in another room, as it is in a current room inwhich the user is present.

FIG. 12 is an explanatory diagram showing an outline of operationscarried out in the home network system for the above conceivableexample.

In the example shown in FIG. 12, the audio reproduction apparatus 3 isreceiving an audio content from the server 1 and reproducing thecontent. In this state, the users enters an operation input to the audioreproduction apparatus 4 to switch the reproduction content from theaudio reproduction apparatus 3 to the audio reproduction apparatus 4 soas to allow the same audio content reproduced so far in the audioreproduction apparatus 3 to be reproduced continuously in the audioreproduction apparatus 4.

In such a case, much like typical operations 1 explained earlier, theserver 1 functions as a media server whereas the audio reproductionapparatus 3 and 4 each function as a media renderer. In addition, eachof the apparatus may have functions of a control point as functions forcontrolling an operation carried out by a server to transmit an audiocontent and an operation carried out by an audio reproduction apparatusto reproduce the content.

As an example, assume a case in which the audio reproduction apparatus 4functions as a control point receiving an operation input. In this case,processing of control points in the apparatus, the media server and themedia renderer can be implemented as the processing represented by theflowcharts shown in FIGS. 8 to 11. However, the audio reproductionapparatus 4 functioning as a control point controls a reproductionoperation in the audio reproduction apparatus 3 through the LAN 6 whilea reproduction operation carried out in the audio reproduction apparatus4 itself is controlled internally. The server 1 functioning as a mediaserver is controlled in accordance with a control packet received fromthe audio reproduction apparatus 4 to switch the operation to transmitan audio content from one transmission destination to another. It is tobe noted that the server 1 can also be controlled by a control point inthe audio reproduction apparatus 3 to transmit an audio content to theaudio reproduction apparatus 3 at an initial time.

A concrete processing procedure for switching the operation to reproducean audio content from the audio reproduction apparatus 3 to the audioreproduction apparatus 4 is explained as follows. First of all, the userenters an operation input to the audio reproduction apparatus 4 to newlydesignate the audio reproduction apparatus 4 itself as the destinationof the operation to transmit the audio content. Receiving such anoperation input, the audio reproduction apparatus 4 requests the server1 to change the destination of the operation to transmit the audiocontent from the audio reproduction apparatus 3 to the audioreproduction apparatus 4. Then, the audio reproduction apparatus 4starts the operation to reproduce the audio content in the audioreproduction apparatus 4 itself. In addition, the audio reproductionapparatus 4 requests the audio reproduction apparatus 3 to end theoperation of reproducing the audio content. At that time, the timing toend the operation of reproducing the audio content in the audioreproduction apparatus 3 can be delayed from the timing to start theoperation of reproducing the audio content in the audio reproductionapparatus 4. On the top of that, the audio reproduction apparatus 3 and4 may be requested to carry out fade-out and fade-in operationsrespectively.

At the request made by the audio reproduction apparatus 4, the server 1puts the data of the currently transmitted audio content in a packetdestined for the audio reproduction apparatus 4 and outputs the packetto the LAN 6. At the same time, the server 1 ends an operation totransmit packets destined for the audio reproduction apparatus 3. Inaddition, in accordance with a control signal received from the audioreproduction apparatus 4, the audio reproduction apparatus 3 ends theoperation to reproduce the audio content. Then, the audio reproductionapparatus 4 receives the data from the server 1 and starts the operationto reproduce the audio content represented by the data.

In the processing described above, the user is capable of switching theoperation to reproduce an audio content from the audio reproductionapparatus 3 to the audio reproduction apparatus 4 and continuing tolisten to a piece of music, which is reproduced in another room of theaudio reproduction apparatus 3, as it is in a specific room in which theuser is present by merely operating only the audio reproductionapparatus 4 located in the specific room. Thus, it is possible to switchthe operation to reproduce an audio content from the audio reproductionapparatus 3 to the audio reproduction apparatus 4 with a high degree ofoperatability.

[Typical Operations 3: Operations for a Plurality of Apparatus Servingas Transmission Destinations and Switching Objects]

In the typical operations 1 and 2 described above, it is assumed thatthe operation to transmit an audio content is switched from a specificaudio reproduction apparatus to another when the content is beingtransmitted to only the specific audio reproduction apparatus. However,the operation to transmit an audio content can also be switched from aspecific audio reproduction apparatus to another when the content isbeing transmitted to a plurality of audio reproduction apparatusincluding the specific audio reproduction apparatus. In addition, aplurality of audio reproduction apparatus can each be newly designatedas an audio reproduction apparatus to start an operation of reproducingan audio content or a plurality of audio reproduction apparatus can eachbe newly specified as an audio reproduction apparatus to end anoperation of reproducing an audio content. As another alternative, aplurality of audio reproduction apparatus can each be newly designatedas an audio reproduction apparatus to start an operation of reproducingan audio content and a plurality of audio reproduction apparatus caneach be specified as an audio reproduction apparatus to end an operationof reproducing an audio content. In order to newly designate a pluralityof audio reproduction apparatus each as an audio reproduction apparatusto start an operation of reproducing an audio content, a control pointgives a command to each of the audio reproduction apparatus as a commandto start an operation of reproducing the audio content. By the sametoken, in order to specify a plurality of audio reproduction apparatuseach as an audio reproduction apparatus to end an operation ofreproducing an audio content, a control point gives a command to each ofthe audio reproduction apparatus as a command to end an operation ofreproducing the audio content. Since the function of the control pointcan be executed by any specific audio reproduction apparatus, byentering an operation input to the specific audio reproductionapparatus, it is possible to carry out the process of switching anoperation to reproduce an audio content from one audio reproductionapparatus or a plurality of audio reproduction apparatus to anotheraudio reproduction apparatus or a plurality of other audio reproductionapparatus.

FIG. 13 is an explanatory diagram showing a typical process of switchingan operation to reproduce an audio content from one audio reproductionapparatus to a plurality of other audio reproduction apparatus.

In the example shown in FIG. 13, while an audio content is beingtransmitted from the server 1 to the audio reproduction apparatus 3 andreproduced in the audio reproduction apparatus 3, the user enters anoperation input to the audio reproduction apparatus 3 to newly designatea plurality of audio reproduction apparatus 4 and 5 each as a contenttransmission destination to start an operation of reproducing the sameaudio content, replacing the audio reproduction apparatus 3.

In this example, assume that the audio reproduction apparatus 3 servesas a control point. In this case, the following procedure is executed toswitch an operation to reproduce an audio content from the audioreproduction apparatus 3 to the audio reproduction apparatus 4 and 5.First of all, the user enters an operation input to the audioreproduction apparatus 3 to newly designate the audio reproductionapparatus 4 and 5 each as a content transmission destination to start anoperation of reproducing the same audio content, replacing the audioreproduction apparatus 3. Then, the audio reproduction apparatus 3requests the server 1 to switch an operation to transmit an audiocontent from the audio reproduction apparatus 3 to the audioreproduction apparatus 4 and 5. Subsequently, the audio reproductionapparatus 3 requests the audio reproduction apparatus 4 and 5 to startan operation of reproducing the audio content and stops the operationcarried out by the audio reproduction apparatus 3 itself to reproducethe audio content. At that time, the timing to end the operation ofreproducing the audio content in the audio reproduction apparatus 3 canbe delayed from the timing to start the operation of reproducing theaudio content in the audio reproduction apparatus 4 and 5 and, inaddition, fade-in and fade-out operations can be carried out during thedelay time.

As requested by the audio reproduction apparatus 3, the server 1 putsthe data of an audio content being transmitted to the audio reproductionapparatus 3 in a packet destined for the audio reproduction apparatus 4and 5, and outputs the packet to the LAN 6. At the same time, the server1 ends the operation to transmit the packet to the audio reproductionapparatus 3. In addition, the audio reproduction apparatus 4 and 5 eachstart an operation to reproduce the audio content in accordance with acontrol signal received from the audio reproduction apparatus 3 whereasthe audio reproduction apparatus 3 ends the operation to reproduce theaudio content. Thus, in the processing described above, by entering anoperation input to the audio reproduction apparatus 3, the operation toreproduce the audio content can be switched from one audio reproductionapparatus 3 to a plurality of audio reproduction apparatus 4 and 5.

[Typical Screens for Selecting Switching Objects]

As described above, the user enters an operation input to select aspecific audio reproduction apparatus as an apparatus to end anoperation of reproducing an audio content and another audio reproductionapparatus as an apparatus to start an operation of reproducing the sameaudio content in order to switch the operation to reproduce the audiocontent from the specific audio reproduction apparatus to the otheraudio reproduction apparatus. A typical screen for allowing the user toenter an operation input for selecting the audio reproduction apparatusis explained as follows.

FIGS. 14 and 15 are each a diagram showing typical screens used forselecting audio reproduction apparatus each to serve as an object ofswitching. FIGS. 14 and 15 sequentially show screens used for selectingaudio reproduction apparatus each to serve as an object of switching inaccordance with select inputs entered by the user. If the user entersoperation inputs to the audio reproduction apparatus 3, for example, thescreens are displayed on the display unit 64 employed in the displayunit 64. In this case, the user can enter the operation inputs bytypically operating the up/down and left/right-direction keys providedon the key operation unit 62 and the remote controller 70.

As shown in the figures, the screen shows an apparatus display portion641 and a function display portion 642. The apparatus display portion641 is a list of the names of selectable audio reproduction apparatus.The function display portion 642 is an area for showing a selectedfunction for an audio reproduction apparatus by using an icon. Byoperating up and down-direction keys, it is possible to change a focusposition indicated by a shadowed block in the figure to the position ofthe name of any audio reproduction apparatus shown on the apparatusdisplay portion 641. With the focus position coinciding with theposition of the name of an audio reproduction apparatus, by operatingthe left and right-direction keys, the display state of the functiondisplay portion 642 can be changed to specify a function assigned to theaudio reproduction apparatus. To put it concretely, for example, theaudio reproduction apparatus can be designated as an audio reproductionapparatus to reproduce an audio content by operating the left andright-direction keys.

The function display portion 642 shows an input-operation reception icon643 having a shape resembling an arrow and a reproduction-apparatus icon644 having a circular shape as shown in the figure. In addition, asshown in FIG. 14A, the input-operation reception icon 643 may bedisplayed, overlapping the reproduction-apparatus icon 644 in somecases. The input-operation reception icon 643 indicates that the audioreproduction apparatus indicated by the input-operation reception icon643 is an audio reproduction apparatus to receive an operation inputfrom the user. On the other hand, the reproduction-apparatus icon 644 ispositioned at the location of an audio reproduction apparatus, which ispresently reproducing an audio content or newly designated as an audioreproduction apparatus to start an operation of reproducing an audiocontent.

As an example, assume a process of switching an operation to reproducean audio content from one audio reproduction apparatus to another byoperating one of the audio reproduction apparatus. The followingdescription explains an operation to select the apparatus to serve asobjects of the switching in such an operation. In FIGS. 14 and 15,apparatus A and B are the audio reproduction apparatus 3 and 4respectively. Much like the example shown in FIG. 7, it is assumed thatthe audio reproduction apparatus 3 reproducing an audio content isoperated to switch the operation to reproduce the audio content from theaudio reproduction apparatus 3 to the audio reproduction apparatus 4.

First of all, when the audio reproduction apparatus 3 is reproducing theaudio content, in this initial state, the input-operation reception icon643 and the reproduction-apparatus icon 644 are displayed at theposition of apparatus A corresponding to the audio reproductionapparatus 3 as shown in FIG. 14A to indicate that the audio reproductionapparatus 3 is an audio reproduction apparatus to receive operationinputs from the user as well as an audio reproduction apparatuscurrently reproducing the audio content. With the focus positioncoinciding with the position of apparatus A, the display states of theinput-operation reception icon 643 and the reproduction-apparatus icon644 on the function display portion 642 can be changed by operating theleft and right-direction keys. It is to be noted that, since the audioreproduction apparatus 3 is assumed to be an audio reproductionapparatus to receive operation inputs from the user, the input-operationreception icon 643 is not moved from its position.

In order to specify the audio reproduction apparatus 3 as an audioreproduction apparatus to terminate the operation to reproduce the audiocontent, the left and right-direction keys are operated to delete thereproduction-apparatus icon 644 beside apparatus A as shown in FIG. 14B.It is to be noted that the audio reproduction apparatus does notactually carries out the requested operation till a confirm key ispressed.

Next, in order to newly designate the audio reproduction apparatus 4 asan audio reproduction apparatus to start an operation of reproducing theaudio content, the up and down-direction keys are operated to change thefocus position in the apparatus display portion 641 to the position ofapparatus B as shown in FIG. 15A. Then, the left and right-directionkeys are operated to display the reproduction-apparatus icon 644 besideapparatus B as shown in FIG. 15B. With the reproduction-apparatus icon644 displayed beside apparatus B as shown in FIG. 14B, apparatus B isnewly designated as an audio reproduction apparatus to start anoperation of reproducing the audio content.

Then, as the confirm key is pressed, the selection of the audioreproduction apparatus 3 as an audio reproduction apparatus to end theoperation of reproducing the audio content and the designation of theaudio reproduction apparatus 4 as an audio reproduction apparatus tonewly start an operation to reproduce the audio content are confirmed.Subsequently, the audio reproduction apparatus 3 requests the server 1to start an operation to transmit the audio content to the audioreproduction apparatus 4 and requests the audio reproduction apparatus 4to start an operation of reproducing the audio content. For example, theaudio reproduction apparatus 3 requests the server 1 to start anoperation to transmit the audio content to the audio reproductionapparatus 4 at the step S206 of the flowchart shown in FIG. 9, andrequests the audio reproduction apparatus 4 to start an operation ofreproducing the audio content at the step S208 or S209 of the sameflowchart. Then, the audio reproduction apparatus 3 requests the server1 to end the operation to transmit the audio content to the audioreproduction apparatus 3 and ends the operation to reproduce the audiocontent. For example, the audio reproduction apparatus 3 requests theserver 1 to end the operation to transmit the audio content to the audioreproduction apparatus 3 at the step S212 of the same flowchart and endsthe operation to reproduce the audio content at the step S213 of thesame flowchart.

The procedure for selecting audio reproduction apparatus as shown inFIGS. 15 and 16 can be applied to a case in which an audio reproductionapparatus receiving operation inputs from the user is newly designatedas an audio reproduction apparatus to start an operation of reproducingan audio content as well as a case in which a plurality of audioreproduction apparatus are each specified as an audio reproductionapparatus to end an operation of reproducing an audio content and aplurality of audio reproduction apparatus are each specified as an audioreproduction apparatus to start an operation of reproducing the audiocontent. As described above, the reproduction-apparatus icon 644 iserased from a position to indicate that the audio reproduction apparatusbeside the position is specified as an audio reproduction apparatus toend an operation of reproducing an audio content and thereproduction-apparatus icon 644 is newly displayed at a position toindicate that the audio reproduction apparatus beside the position isnewly designated as an audio reproduction apparatus to start anoperation of reproducing an audio content.

[Automatic Selection of Audio Reproduction Apparatus as SwitchingObjects]

The processing to specify an audio reproduction apparatus as an audioreproduction apparatus to end an operation of reproducing an audiocontent and newly designate an audio reproduction apparatus as an audioreproduction apparatus to start an operation of reproducing an audiocontent as described above can be carried out automatically by callinginformation set in advance as information identifying the audioreproduction apparatus selected as objects of switching. For example,information on audio reproduction apparatus is stored in advance in amemory to be called later and supplied to a control point. The storedinformation is information identifying an audio reproduction apparatusarbitrarily specified by the user as an audio reproduction apparatus toend an operation of reproducing an audio content, an audio reproductionapparatus newly designated in an arbitrary manner by the user as anaudio reproduction apparatus to start an operation of reproducing anaudio content, an audio reproduction apparatus specified by the user inan immediately previous selection process as an audio reproductionapparatus to end an operation of reproducing an audio content and anaudio reproduction apparatus newly designated in an immediately previousselection process by the user as an audio reproduction apparatus tostart an operation of reproducing an audio content.

FIG. 16 shows a typical table used by an audio reproduction apparatusspecified as a switching object to end an operation of reproducing anaudio content as a table showing audio reproduction apparatus each to benewly designated as a switching object to start an operation ofreproducing the audio content. To be more specific, FIG. 16 shows atypical table stored in an audio reproduction apparatus, which isspecified as a switching object to end an operation of reproducing anaudio content, as a table showing audio reproduction apparatus each tobe newly designated as a switching object to start an operation ofreproducing the audio content. This typical table is a table used forstoring both set information 551 a on an audio reproduction apparatus,which was newly designated as a switching object to start an operationof reproducing an audio content in an immediately previous switchingprocess, and information 551 b on audio reproduction apparatus set byusers as audio reproduction apparatus each to be newly designated as aswitching object to start an operation of reproducing an audio content.Thus, when an operation input making a request for switching of anoperation to reproduce an audio content, an audio reproduction apparatusset in the table can be used as an audio reproduction apparatus to benewly designated as a switching object to start the operation ofreproducing an audio content.

In this typical table, the information on an audio reproductionapparatus to be newly designated as a switching object to start anoperation of reproducing an audio content includes the newly designatedapparatus 552 in switching of the audio reproduction apparatus, a MAC(Media Access Control) address 553, a switching duration 554 and a flag555. The MAC address 553 is an address used for identifying the audioreproduction apparatus. The switching duration 554 is the length of timeit takes to carry out the switching operation. The flag 555 is a flagindicating whether or not fade-in and fade-out operations are to becarried out. If a plurality of audio reproduction apparatus are eachspecified as an audio reproduction apparatus to be newly designated as aswitching object to start an operation of reproducing an audio content,the information 551 b is set as information including the newlydesignated apparatus 552 in switching of the audio reproductionapparatus and their MAC addresses 553.

Typically, this table is stored in the flash memory 55 employed in theaudio reproduction apparatus such as the audio reproduction apparatus 3.When an audio reproduction apparatus is specified as an audioreproduction apparatus to be newly designated as a switching object tostart an operation of reproducing an audio content at, for example, thesteps S201 to S204 of the flowchart shown in FIG. 9, the pieces ofinformation are read out from the table and used as a base of adisplayed select screen. Then, by referring to the displayed selectscreen, the user can enter an input selecting ones of the audioreproduction apparatus. In addition, the set information 551 a on anaudio reproduction apparatus, which was newly designated as a switchingobject to start an operation of reproducing an audio content in animmediately previous switching process, is updated at a point of timethe select input entered by the user is confirmed for example when adetermination result produced at the step S205 of the flowchart shown inFIG. 9 reveals that the input is verified to be a correct input.

The processing to read out information from the table and update the setinformation 551 a is typically carried out by execution of a controlapplication program for a process of presenting a U/I (user interface)or a program for implementing a function of a control point. If theprocessing is carried out by execution of a control application programfor a process of presenting a U/I, for example, the pieces ofinformation are read out from the table and used as a base of adisplayed select screen. Then, by referring to the displayed selectscreen, the user can enter an input selecting ones of the audioreproduction apparatus. In this case, the selected information issupplied to a control point to inform the control point of a selectedaudio reproduction apparatus. In addition, at this point of time, theset information 551 a is updated on the basis of the selectedinformation. Thus, in this processing, the user can carry out a processto switch an operation to reproduce an audio content from an audioreproduction apparatus to another by carrying out a simple inputoperation.

It is to be noted that the table described above may includedescriptions of devices provided in each audio reproduction apparatusspecified as a switching object to end an operation of reproducing anaudio content and each audio reproduction apparatus to be newlydesignated as a switching object to start an operation of reproducing anaudio content. In addition, the table may include descriptions ofservices rendered by each of the audio reproduction apparatus,information on contents (such as album information and trackinformation) to be distributed and an IP address for identifying each ofthe audio reproduction apparatus.

[Limitations on Control Points Capable of Controlling Media Renderers]

As described above, in this embodiment, all apparatus connected to theLAN 6 are capable of functioning as a control point. In consequence, inthe course of a process to switch an operation to reproduce an audiocontent from one audio reproduction apparatus to another, a controlpoint other than a control point controlling this switching process maygenerate a control signal to a specific audio reproduction apparatusbeing subjected to the switching process in some cases. It isundesirable to have a reproduction operation of such a specific audioreproduction apparatus controlled by a control signal generated by theother control point in the course of a process to switch an operation toreproduce an audio content.

It is thus desirable to provide an audio reproduction apparatusreceiving an operation input and an audio reproduction apparatus servingas an object of a switching process with a function to reject a controlsignal transmitted by another control point during at least a periodbetween the start of the operation input to switch an operation toreproduce an audio signal from one audio reproduction apparatus toanother and the end of the switching operation. To put it concretely,for example, an audio reproduction apparatus serving as an object of theswitching process holds information identifying a controlling audioreproduction apparatus and, when the audio reproduction apparatusserving as an object of the switching process receives controlinformation from an audio reproduction apparatus other than thecontrolling audio reproduction apparatus in the course of the switchingprocess, the audio reproduction apparatus serving as an object of theswitching process just discards a request based on this controlinformation and merely informs the audio reproduction apparatus otherthan the controlling audio reproduction apparatus that the request hasbeen discarded.

[Others]

A computer is capable of implementing the processing functions of acontrol point, a media server and a media renderer, which are employedin the embodiment. In this case, programs are used for prescribing thecontents of processing of the functions that an audio reproductionapparatus and a server should have. The computer executes the program tocarry out the processing. The programs used for prescribing thesubstance of the processing can be stored in advance in a recordingmedium that can be read by the computer. Examples of the recordingmedium are a magnetic recording medium, an optical disk, amagneto-optical disk and a semiconductor memory.

The programs are delivered to users by storing the programs in portablerecording mediums such as semiconductor memories and selling theportable recording mediums to the users. As an alternative, the programsare stored in advance in a storage unit employed in a computer of aserver to be distributed to other computers from the computer of theserver by way of the network.

A computer for executing the programs install the programs fromtypically the portable recording medium or the network in case theprograms are distributed from the server into a storage unit of thecomputer itself. Then, the computer reads out a program from the storageunit of the computer itself and executes the program to carry outprocessing. It is to be noted that the computer is also capable ofexecuting the program by reading out the program directly from theportable recording medium.

In addition, in the embodiment described above, a server has only thefunction of a media server. However, the server can also include thefunction of a media renderer besides the function of a media server. Inthis case, the server can be specified as an audio reproductionapparatus to newly start an operation of reproducing an audio content oran audio reproduction apparatus to end an operation of reproducing theaudio content in a process to switch reproduction of a content from theaudio reproduction apparatus to end the reproduction of the content tothe audio reproduction apparatus to newly start reproduction of the samecontent.

Furthermore, a content distributed by a media server to be reproduced bya media renderer can be information such as a video content, astill-picture content or a text content such news besides an audiocontent described above.

Moreover, the embodiment applies the present invention to a home networksystem conforming to the conforming to the UPnP (Universal Plug & Play)specifications. However, the present invention can also be applied toother network systems conforming to Jini (Java (a trademark) intelligentnetwork infrastructure) or HAVi (Home Audio/Video interoperability)specifications. That is to say, the present invention can be applied toa variety of network systems each including servers each functioning asa provider of a variety of contents such as an audio content and clientseach receiving a content from a server and sequentially reproducing thecontent.

While the preferred embodiments of the present invention have beendescribed using specific embodiments, such description is forillustrative purposes only, and it is to be understood that changes andvariations may be made without departing from the spirit or scope of theappended claims.

What is claimed is:
 1. A method for use in a system comprising an information processing apparatus, the method comprising acts of: (A) acquiring, by the information processing apparatus, audio content identification information indicating audio content data, server identification information indicating a server which transmits the audio content data to an audio reproduction apparatus on a network, and transmission destination information indicating an audio reproduction apparatus to receive the audio content data from the server; and (B) transmitting, by the information processing apparatus, a request for starting transmission of the audio content to the server, based on the acquired audio content identification information, the server identification information, and the transmission destination information.
 2. At least one non-transitory computer-readable medium having computer-executable instructions stored thereon which, when executed by at least one computer processor, cause the at least one computer processor to execute a method, the method comprising acts of: (A) acquiring, by the at least one processor, audio content identification information indicating audio content data, server identification information indicating a server which transmits the audio content data to an audio reproduction apparatus on a network, and transmission destination information indicating an audio reproduction apparatus to receive the audio content data from the server; and (B) transmitting, by the at least one processor, a request for starting transmission of the audio content to the server, based on the acquired audio content identification information, the server identification information, and the transmission destination information.
 3. An information processing apparatus comprising: at least one computer processor, programmed to: acquire audio content identification information indicating audio content data, server identification information indicating a server which transmits the audio content data to an audio reproduction apparatus on a network, and transmission destination information indicating an audio reproduction apparatus to receive the audio content data from the server; and transmit a request for starting transmission of the audio content to the server, based on the acquired audio content identification information, the server identification information, and the transmission destination information. 